Tüm alıştırma soruları

Soru 821Soru →

An electronics technician is analyzing the atomic structure and thermal-electrical properties of three unknown solid materials for a specialized circuit application. Material X possesses exactly four valence electrons and its electrical conductivity increases when heated. Material Y possesses a single, loosely bound valence electron and its electrical conductivity decreases when heated. Material Z has a completely filled outermost shell with tightly bound valence electrons. Based on these fundamental characteristics, which of the following correctly classifies these three materials?

Material X is a semiconductor, Material Y is a conductor, and Material Z is an insulator.

Material X is a conductor, Material Y is a semiconductor, and Material Z is an insulator.

Material X is an insulator, Material Y is a conductor, and Material Z is a semiconductor.

Material X is a semiconductor, Material Y is an insulator, and Material Z is a conductor.

Cevabı ve açıklamayı göster

Cevap: Material X is a semiconductor, Material Y is a conductor, and Material Z is an insulator.

Cevap

Material X is a semiconductor, Material Y is a conductor, and Material Z is an insulator.

The correct answer accurately synthesizes the relationship between atomic structure and electrical behavior. Semiconductors (Material X) are defined by having exactly 4 valence electrons; as they are heated, thermal energy frees more electrons, increasing conductivity. Conductors (Material Y) typically have 1 to 3 loosely bound valence electrons; as they are heated, increased atomic vibrations impede electron flow, decreasing conductivity. Insulators (Material Z) are characterized by full, tightly bound valence shells, preventing electron flow entirely.

Adım Adım Çözüm

1

Analyze the properties of Material X.

Material X is identified as a semiconductor.

It has exactly four valence electrons (Group IV elements like Silicon and Germanium) and its conductivity increases with heat (negative temperature coefficient of resistance) as thermal energy pushes electrons across the narrow band gap.

2

Analyze the properties of Material Y.

Material Y is identified as a conductor.

It has a single loosely bound valence electron (like Copper, Silver, or Gold), which makes it highly conductive. Its conductivity decreases with heat (positive temperature coefficient) due to increased atomic lattice vibrations scattering the free electrons.

3

Analyze the properties of Material Z.

Material Z is identified as an insulator.

It has a completely filled outermost shell with tightly bound electrons (like Mica or Glass), meaning there are no free electrons available for electrical conduction under normal conditions.

4

Combine the evaluations to select the correct classification.

The correct classification is: X = semiconductor, Y = conductor, Z = insulator.

This is the only combination that accurately aligns with the fundamental atomic and thermal theories of electrical materials.

Anahtar Kavram

Atomic structure (valence electrons) and thermal-electrical properties of basic electronic materials.

Tahmini Süre:1m 30s

Soru 822Soru →

In electrical circuits, the physical characteristics of a conductor govern its opposition to current flow. Match each conductor modification on the left with its resulting effect on electrical resistance on the right.

Soldaki öğeye tıklayın, sonra eşleşen sağdaki öğeye tıklayın

Cevabı ve açıklamayı göster

Cevap

Extending length matches with increasing resistance due to a longer path; increasing diameter matches with decreasing resistance due to a wider cross-section; elevating temperature matches with increasing resistance due to increased atomic vibrations; replacing copper with nichrome matches with increasing resistance due to higher intrinsic resistivity.

Each modification is correctly paired according to the fundamental resistance formula

R = \rho \frac{L}{A}

and the positive temperature coefficient of metallic conductors: increasing length increases

R

, increasing cross-sectional area decreases

R

, heating the metal increases

R

, and selecting a higher resistivity material increases

R

.

Adım Adım Çözüm

1

Analyze the relationship between wire length and resistance using

R = \rho \frac{L}{A}

Resistance increases linearly as length increases.

Electrons encounter more resistive material over a longer distance.

2

Analyze the relationship between wire cross-sectional area (thickness) and resistance

Resistance decreases as area increases.

A greater cross-sectional area allows more electrons to pass simultaneously with fewer collisions.

3

Determine the effect of thermal energy on metallic conductors

Resistance increases as temperature rises.

Thermal energy causes metal lattice ions to vibrate more vigorously, impeding the drift of free electrons.

4

Compare material resistivity (

\rho

) between copper and nichrome

Nichrome creates greater resistance than copper of identical dimensions.

Nichrome is a high-resistivity alloy specifically designed to impede current flow and generate heat.

Anahtar Kavram

The resistance of a conductor is determined by its physical dimensions (length and cross-sectional area), material resistivity, and operating temperature.

Tahmini Süre:45s

Soru 823Soru →

Electromagnetic components are essential for controlling current and voltage levels in alternating current circuits. Which characteristic or operational principle correctly corresponds to each listed component or term?

Soldaki öğeye tıklayın, sonra eşleşen sağdaki öğeye tıklayın

Cevabı ve açıklamayı göster

Cevap

Step-up transformer matches a device with more secondary turns than primary turns that increases alternating voltage; Inductor matches a device that opposes rapid changes in electric current by storing energy in a magnetic field; Henry matches the standard unit of measurement for electrical inductance; Mutual induction matches the process by which a changing current in one coil induces an electromotive force in an adjacent coil.

Each item is matched to its exact operational role and definition: the step-up transformer increases AC voltage via a greater secondary turn count; the inductor resists current changes through magnetic storage; the henry serves as the unit of inductance; and mutual induction represents the principle of transferring energy across coupled coils.

Adım Adım Çözüm

1

Identify the function of a step-up transformer.

A step-up transformer increases alternating voltage because its secondary winding has more turns than its primary winding (

N_s > N_p

).

According to the transformer turns ratio formula,

\frac{V_s}{V_p} = \frac{N_s}{N_p}

, higher secondary turns produce higher secondary voltage.

2

Identify the operating behavior of an inductor.

An inductor resists sudden current fluctuations by temporarily storing electrical energy in a concentrated magnetic field.

Lenz's law states that the induced back-EMF always acts to oppose the original change in current.

3

Identify the standard unit for inductance.

The henry (

\text{H}

) is the recognized unit of electrical inductance.

One henry of inductance induces an electromotive force of one volt when the current changes at a rate of one ampere per second.

4

Identify the definition of mutual induction.

Mutual induction is the magnetic coupling effect where current variations in a primary winding induce a voltage across a separate secondary winding.

This electromagnetic linkage allows electrical energy to transfer between isolated circuits without direct conductive contact.

Anahtar Kavram

Core definitions, units, and operational characteristics of inductors and transformers

Tahmini Süre:45s

Soru 824Soru →

While diagnosing a control circuit in an industrial machine, a technician measures the flow of electric current through a closed direct-current (DC) loop. Which statement accurately describes the relationship between the electrical current and charge carriers in this circuit?

Electric current is the electromotive pressure maintained across terminals that exists even when no physical charge is in motion.

Electric current is the continuous rate of charge transfer through the conductor, produced by free electrons drifting toward the positive potential.

Electric current in this DC circuit continuously reverses direction back and forth through the load at a standard cyclic frequency.

Electric current is the movement of bound atomic charges traveling exclusively along the outer protective insulating sheath.

Cevabı ve açıklamayı göster

Cevap: Electric current is the continuous rate of charge transfer through the conductor, produced by free electrons drifting toward the positive potential.

Cevap

Electric current is the continuous rate of charge transfer through the conductor, produced by free electrons drifting toward the positive potential.

Electric current is defined as the rate at which charge passes through a cross-section of a conductor (

I = Q/t

). In standard solid conductors under direct current (DC), the charge carriers are mobile valence electrons that drift unidirectionally toward the positive terminal of the circuit.

Adım Adım Çözüm

1

Identify the fundamental definition of electric current.

Current (

I

) is defined as the quantity of electrical charge (

Q

) passing a cross-section of a conductor per unit of time (

t

), expressed mathematically as

I = \frac{Q}{t}

.

Establishing the definition of current separates it from static potential or resistance.

2

Determine the physical charge carrier behavior in a direct-current metallic circuit.

In metallic conductors, current is carried by negatively charged free valence electrons that drift away from the negative polarity toward the positive terminal in a unidirectional path.

Direct current maintains a constant single direction of charge carrier drift.

Anahtar Kavram

Electric current is the time rate of charge flow through a conductor, with electrons physically moving toward the positive terminal in a DC circuit.

Tahmini Süre:45s

Soru 825Soru →

Match each Watt's Law power formula or electrical power unit on the left with its corresponding definition or application condition on the right.

Soldaki öğeye tıklayın, sonra eşleşen sağdaki öğeye tıklayın

Cevabı ve açıklamayı göster

Cevap

P = V \times I

matches power from voltage and current;

P = I^2 R

matches power from current and resistance;

P = \frac{V^2}{R}

matches power from voltage and resistance;

1\text{ Watt (W)}

matches the unit equivalent to one joule per second.

Each formula represents a direct algebraic variation of Watt's Law derived by combining

P = V \times I

with Ohm's Law (

V = IR

), and the watt is defined as one joule per second.

Adım Adım Çözüm

1

Identify the base relationship of Watt's Law

P = V \times I

Electrical power is defined as the rate at which electrical energy is transferred, calculated by multiplying voltage across a load by the current flowing through it.

2

Derive the formula relating power to current and resistance

P = I^2 R

By substituting

V = I \times R

from Ohm's Law into

P = V \times I

, power is expressed in terms of current squared times resistance.

3

Derive the formula relating power to voltage and resistance

P = \frac{V^2}{R}

By substituting

I = \frac{V}{R}

from Ohm's Law into

P = V \times I

, power is expressed in terms of voltage squared divided by resistance.

4

Identify the standard unit and definition of power

1\text{ W} = 1\text{ J/s}

Power measures the rate of doing work or dissipating energy, where one watt equals one joule per second.

Anahtar Kavram

Watt's Law and Electrical Power Formulas

Tahmini Süre:45s

Soru 826Soru →

An electronics technician is testing a DC bias circuit containing a fixed resistor connected to an adjustable DC power supply. When the supply voltage is set to $28\text{ V}$ , the circuit ammeter measures a current of $3.5\text{ mA}$ . To increase the current flow through the resistor to $11\text{ mA}$ , what must the power supply voltage be set to?

60\text{ V}

8.8\text{ V}

88\text{ V}

22\text{ V}

Cevabı ve açıklamayı göster

Cevap: $88\text{ V}$

Cevap

The power supply voltage must be set to

88\text{ V}

.

The power supply must be set to

88\text{ V}

. First, determine the component's constant resistance:

R = \frac{28\text{ V}}{3.5\text{ mA}} = 8\text{ k}\Omega

. Next, apply Ohm's Law to find the voltage required for the target current:

V = 11\text{ mA} \times 8\text{ k}\Omega = 88\text{ V}

. Alternatively, using direct proportionality:

V_2 = 28\text{ V} \times \left(\frac{11\text{ mA}}{3.5\text{ mA}}\right) = 88\text{ V}

.

Adım Adım Çözüm

1

Calculate the fixed resistance using the initial voltage and current measurements.

R = \frac{V_1}{I_1} = \frac{28\text{ V}}{3.5\text{ mA}} = \frac{28\text{ V}}{0.0035\text{ A}} = 8{}000\,\Omega = 8\text{ k}\Omega

Ohm's Law defines resistance as the ratio of voltage to current (

R = \frac{V}{I}

).

2

Calculate the new voltage required to produce

11\text{ mA}

through the

8\text{ k}\Omega

resistor.

V_2 = I_2 \times R = 0.011\text{ A} \times 8{}000\,\Omega = 88\text{ V}

Applying Ohm's Law in the form

V = I \times R

determines the potential difference needed for the desired current.

Anahtar Kavram

Ohm's Law defines the fundamental linear relationship between voltage, current, and resistance in a DC circuit (

V = I \times R

). In a circuit with constant resistance, voltage is directly proportional to current.

Alternatif Yöntem

Because resistance is constant, voltage is directly proportional to current:

V_2 = V_1 \times \frac{I_2}{I_1} = 28\text{ V} \times \frac{11\text{ mA}}{3.5\text{ mA}} = 28 \times \frac{22}{7} = 4 \times 22 = 88\text{ V}

.

Tahmini Süre:45s

Soru 827Soru →

Fill in the blanks to complete the statement describing how overcurrent protective devices are connected and restored in an electrical circuit.

Aşağıdaki boşlukları doldurun

To protect a circuit from excessive current, a protective device such as a fuse or circuit breaker must always be connected in with the load. Unlike a one-time fuse that melts its element and must be replaced, a standard circuit breaker can simply be after the fault is cleared.

Cevabı ve açıklamayı göster

Cevap

blank_1: series; blank_2: reset

Overcurrent protective devices like fuses and circuit breakers must always be installed in series with the load so that the full circuit current passes through them. If an overcurrent or short circuit occurs, opening the device breaks the single path for current flow, completely de-energizing the circuit. Additionally, while fuses contain a sacrificial metal strip that melts and requires complete replacement after opening, circuit breakers utilize reusable mechanical contacts that can be manually reset to restore normal operation.

Adım Adım Çözüm

1

Determine the required wiring configuration for an overcurrent protection device.

Protective devices must be placed in series with the load.

Connecting the protective device in series ensures that all circuit current flows through it, allowing it to interrupt the entire current path when an overload occurs.

2

Identify the restoration method for a tripped circuit breaker compared to a blown fuse.

A circuit breaker can be mechanically reset.

Fuses rely on a sacrificial metal link that melts permanently when rated current is exceeded, whereas circuit breakers use reusable mechanical contacts that open and can be manually reset.

Anahtar Kavram

Overcurrent protective device circuit placement and operational restoration

Tahmini Süre:45s

Soru 828Soru →

An electronics technician observes that inside an uncooled avionics chassis, a pure silicon diode demonstrates a significant decrease in internal resistance as ambient temperature climbs, whereas surrounding standard copper wiring exhibits increased resistance. What is the primary atomic mechanism that causes the electrical conductivity of an intrinsic semiconductor to increase as temperature rises?

Thermal expansion forces the four valence electrons to tightly lock into covalent bonds, preventing atomic vibration and allowing current to pass unimpeded.

Thermal energy breaks covalent bonds within the crystal lattice, exciting valence electrons across the forbidden band gap into the conduction band to generate free electron-hole pairs.

Increased temperature accelerates the drift velocity of preexisting free electrons, eliminating collisions between charge carriers and the stationary nucleus.

The semiconductor atom's outer shell absorbs free electrons from neighboring insulator jackets, increasing the net negative charge and converting the material into an active voltage source.

Cevabı ve açıklamayı göster

Cevap: Thermal energy breaks covalent bonds within the crystal lattice, exciting valence electrons across the forbidden band gap into the conduction band to generate free electron-hole pairs.

Cevap

Thermal energy excites valence electrons across the forbidden energy gap into the conduction band, creating free electron-hole pairs that increase conductivity.

In intrinsic semiconductors such as pure silicon, the valence band is nearly full and the conduction band is nearly empty at low temperatures, separated by a relatively narrow forbidden band gap (approximately 1.1 eV for silicon). When temperature rises, thermal agitation provides sufficient kinetic energy to break covalent bonds, exciting valence electrons across this gap into the conduction band. This process generates both free conduction electrons and mobile holes, dramatically increasing the carrier density and lowering the material's electrical resistance (negative temperature coefficient of resistance).

Adım Adım Çözüm

1

Analyze the valence electron structure of intrinsic semiconductors (Group IV elements like silicon and germanium).

Silicon has four valence electrons that form covalent bonds with four adjacent atoms in a crystalline lattice, leaving virtually zero free electrons at absolute zero.

Understanding the baseline atomic bonding of semiconductors is essential to distinguish them from metallic conductors with abundant free electrons.

2

Evaluate the effect of thermal energy on semiconductor covalent bonds versus metallic conductors.

In metals, heating increases lattice vibrations, causing greater electron scattering and higher resistance (positive temperature coefficient). In semiconductors, heat supplies energy to break covalent bonds, promoting electrons across the narrow forbidden band gap into the conduction band.

This explains the negative temperature coefficient of resistance characteristic of intrinsic semiconductors.

3

Identify the resulting charge carriers and impact on electrical conductivity.

Each liberated electron creates a free negative carrier in the conduction band and leaves behind a positive vacancy (hole) in the valence band, drastically increasing total charge carrier concentration and reducing resistance.

Conductivity is directly proportional to the concentration of mobile charge carriers.

Anahtar Kavram

Semiconductor Temperature Coefficient and Electron-Hole Pair Generation

Tahmini Süre:1m 30s

Soru 829Soru →

An automotive technician tests a fuel level sensor module connected to a $12\text{ V}$ direct current (DC) supply. An in-line digital multimeter measures a steady current flow of $15\text{ mA}$ through the module. What is the electrical resistance of the sensor module?

0.8\text{ }\Omega

1.25\text{ }\Omega

800\text{ }\Omega

180\text{ }\Omega

Cevabı ve açıklamayı göster

Cevap: $800\text{ }\Omega$

Cevap

The electrical resistance of the sensor module is

800\text{ }\Omega

.

According to Ohm's law, resistance equals voltage divided by current (

R = \frac{V}{I}

). Converting

15\text{ mA}

to amperes gives

0.015\text{ A}

. Dividing

12\text{ V}

by

0.015\text{ A}

yields

800\text{ }\Omega

.

Adım Adım Çözüm

1

Convert the measured current from milliamperes (mA) to the base SI unit amperes (A).

I = 15\text{ mA} = 15 \times 10^{-3}\text{ A} = 0.015\text{ A}

Standard electrical formulas require quantities in base units (volts, amperes, ohms).

2

State Ohm's law rearranged to solve for resistance (

R

).

R = \frac{V}{I}

Resistance equals electromotive force (voltage) divided by current flow.

3

Substitute the given values into the formula and calculate the resistance.

R = \frac{12\text{ V}}{0.015\text{ A}} = \frac{12000}{15}\text{ }\Omega = 800\text{ }\Omega

Dividing

12\text{ V}

by

0.015\text{ A}

yields the total circuit resistance in ohms.

Anahtar Kavram

Ohm's Law (

V = I \times R

) defines the relationship between voltage, current, and resistance in a DC circuit.

Tahmini Süre:45s

Soru 830Soru →

A technician is evaluating the electrical characteristics of a direct-current parallel circuit network. Match each circuit parameter on the left with its corresponding behavior or rule on the right.

Soldaki öğeye tıklayın, sonra eşleşen sağdaki öğeye tıklayın

Cevabı ve açıklamayı göster

Cevap

Branch Voltage matches 'Remains constant and equal across all connected branches'; Total Current matches 'Equals the sum of the individual currents flowing through all branches'; Equivalent Resistance matches 'Is always lower than the resistance of the smallest branch resistor'; Branch Current matches 'Varies inversely with the branch resistance according to

I = \frac{V}{R}

'.

In parallel circuits, all components share common connection points, maintaining equal voltage across each branch. Total current equals the sum of all individual branch currents. Total equivalent resistance decreases as more branches are added (remaining less than the smallest branch resistance). Individual branch current is calculated via Ohm's Law as voltage divided by that branch's resistance.

Adım Adım Çözüm

1

Determine the voltage relationship across parallel branches.

Branch Voltage (

V_{\text{branch}}

) is equal across all branches (

V_{\text{total}} = V_1 = V_2 = \dots

).

All branches connect across the same two common nodes to the power supply.

2

Determine the total current relationship for a parallel network.

Total Current (

I_{\text{total}}

) equals the sum of branch currents (

I_{\text{total}} = I_1 + I_2 + \dots

).

Current splits at junction nodes according to Kirchhoff's Current Law.

3

Determine how total equivalent resistance behaves in a parallel circuit.

Equivalent Resistance (

R_{\text{eq}}

) is always smaller than the smallest branch resistance.

Adding parallel branches adds additional conductive paths for electron flow.

4

Determine how current through a specific branch is calculated.

Branch Current (

I_{\text{branch}}

) is calculated using Ohm's Law (

I_{\text{branch}} = \frac{V}{R_{\text{branch}}}

).

Branch current depends on the common branch voltage divided by the individual branch resistance.

Anahtar Kavram

Fundamental rules governing voltage, current, and resistance in DC parallel circuits.

Tahmini Süre:45s

Soru 831Soru →

A military vehicle communication module is powered by a $60\text{ V}$ DC supply connected in series with three resistive components: a fixed input resistor $R_1 = 40\ \Omega$ , an unknown matching resistor $R_2$ , and a load resistor $R_3 = 80\ \Omega$ . If a technician measures a voltage drop of $12\text{ V}$ across resistor $R_1$ , what is the resistance value of $R_2$ ?

40\ \Omega

160\ \Omega

80\ \Omega

200\ \Omega

Cevabı ve açıklamayı göster

Cevap: $80\ \Omega$

Cevap

80\ \Omega

Because current is uniform throughout a single series path, the current through the entire circuit is determined by the known component

R_1

:

I = \frac{12\text{ V}}{40\ \Omega} = 0.3\text{ A}

. With a

60\text{ V}

supply, the total circuit resistance is

R_T = \frac{60\text{ V}}{0.3\text{ A}} = 200\ \Omega

. Since

R_T = R_1 + R_2 + R_3

, subtracting the known values gives

R_2 = 200\ \Omega - 40\ \Omega - 80\ \Omega = 80\ \Omega

.

Adım Adım Çözüm

1

Calculate the common series loop current using Ohm's Law across the first known resistor.

I = \frac{V_1}{R_1} = \frac{12\text{ V}}{40\ \Omega} = 0.3\text{ A}

In a series circuit, the current is identical at all points along the loop.

2

Calculate the total equivalent resistance of the circuit using the total supply voltage and loop current.

R_T = \frac{V_{\text{total}}}{I} = \frac{60\text{ V}}{0.3\text{ A}} = 200\ \Omega

Ohm's Law relates the source voltage to the total circuit resistance and total current.

3

Subtract the known series resistances from the total circuit resistance to isolate the unknown resistor.

R_2 = R_T - R_1 - R_3 = 200\ \Omega - 40\ \Omega - 80\ \Omega = 80\ \Omega

Total resistance in a series circuit is the algebraic sum of all individual resistances (

R_T = R_1 + R_2 + R_3

).

Anahtar Kavram

In a series circuit, current remains constant through every component, and total circuit resistance is the sum of individual resistances (

R_T = R_1 + R_2 + R_3

).

Alternatif Yöntem

Find the loop current

I = \frac{12\text{ V}}{40\ \Omega} = 0.3\text{ A}

. Then find the voltage drop across

R_3

:

V_3 = 0.3\text{ A} \times 80\ \Omega = 24\text{ V}

. Using Kirchhoff's Voltage Law, find the voltage drop across

R_2

:

V_2 = 60\text{ V} - 12\text{ V} - 24\text{ V} = 24\text{ V}

. Finally, calculate

R_2 = \frac{V_2}{I} = \frac{24\text{ V}}{0.3\text{ A}} = 80\ \Omega

.

Tahmini Süre:1m 30s

Soru 832Soru →

An electric vehicle telemetry subsystem is powered by a $45\text{ V}$ direct current (DC) source connected in series with three resistive sensors: $R_1 = 7\ \Omega$ , $R_2 = 11\ \Omega$ , and $R_3 = 12\ \Omega$ . What is the voltage drop across the $11\ \Omega$ sensor ( $R_2$ )?

15.0\text{ V}

16.5\text{ V}

45.0\text{ V}

1.5\text{ V}

Cevabı ve açıklamayı göster

Cevap: $16.5\text{ V}$

Cevap

16.5\text{ V}

(the voltage drop across the

11\ \Omega

resistor)

The correct answer is

16.5\text{ V}

. In a series circuit, total resistance is found by adding all individual resistors (

7\ \Omega + 11\ \Omega + 12\ \Omega = 30\ \Omega

). Dividing the

45\text{ V}

source by the

30\ \Omega

total resistance yields a circuit current of

1.5\text{ A}

. Multiplying this

1.5\text{ A}

current by the

11\ \Omega

resistance of the specified resistor gives a voltage drop of

16.5\text{ V}

.

Adım Adım Çözüm

1

Calculate the total series resistance (

R_T

) by summing the three individual resistances.

R_T = R_1 + R_2 + R_3 = 7\ \Omega + 11\ \Omega + 12\ \Omega = 30\ \Omega

In a series circuit, equivalent resistance equals the sum of all individual resistances in the loop.

2

Calculate the total loop current (

I

) using Ohm's Law.

I = \frac{V_T}{R_T} = \frac{45\text{ V}}{30\ \Omega} = 1.5\text{ A}

Current remains constant and identical through all components in a series loop.

3

Calculate the voltage drop across

R_2

using Ohm's Law.

V_2 = I \times R_2 = 1.5\text{ A} \times 11\ \Omega = 16.5\text{ V}

The voltage drop across any individual resistor is the product of the common loop current and that resistor's resistance.

Anahtar Kavram

In a series circuit, current is identical through every component, and the source voltage divides across each resistor in direct proportion to its resistance value (

V_x = I \times R_x

).

Alternatif Yöntem

Use the voltage divider formula:

V_2 = V_T \times \left(\frac{R_2}{R_T}\right) = 45\text{ V} \times \left(\frac{11\ \Omega}{30\ \Omega}\right) = 16.5\text{ V}

.

Tahmini Süre:1m 0s

Soru 833Soru →

What is required to induce an electric current in a stationary coil of wire using a magnet?

A constant, stationary magnetic field held next to the coil

Relative motion between the magnetic field and the coil

An electrostatic charge stored inside an insulating dielectric

A fixed potential difference that prevents magnetic line movement

Cevabı ve açıklamayı göster

Cevap: Relative motion between the magnetic field and the coil

Cevap

Relative motion between the magnetic field and the coil is required to induce an electric current.

According to the principle of electromagnetic induction, an electric current is generated in a conductor when magnetic lines of force cut across the wire. This requires relative motion between the magnetic field and the coil, creating a changing magnetic flux that produces an electromotive force (voltage).

Adım Adım Çözüm

1

Identify the fundamental principle of electromagnetic induction defined by Faraday's Law.

An electromotive force (EMF) is induced in a wire loop only when the loop experiences a changing magnetic flux.

Stationary magnetic fields do not cut across stationary conductors, producing zero induced voltage.

2

Determine the physical condition necessary to produce this change in magnetic flux.

There must be relative motion between the magnet and the coil so that magnetic lines of force cut across the turns of wire.

Moving the magnet relative to the coil causes the magnetic flux density through the coil to vary with time, driving electron movement.

Anahtar Kavram

Faraday's Law of Electromagnetic Induction

Tahmini Süre:45s

Soru 834Soru →

A box contains a mixture of red, blue, and green tokens. There are exactly $16$ red tokens in the box. The probability of randomly selecting a red token is $\frac{2}{5}$ . If there are $14$ blue tokens in the box, what is the probability of randomly selecting a green token on a single draw?

\frac{1}{4}

\frac{3}{5}

\frac{7}{20}

\frac{1}{3}

Cevabı ve açıklamayı göster

Cevap: $\frac{1}{4}$

Cevap

The probability of randomly selecting a green token is

\frac{1}{4}

.

To find the probability of drawing a green token, you must first know the total number of tokens. Because the

16

red tokens make up

\frac{2}{5}

of the total, the total number of tokens is

16 \div \frac{2}{5} = 40

. The box contains

16

red and

14

blue tokens, accounting for

30

tokens. This leaves

10

green tokens (

40 - 30

). The probability of selecting a green token is the number of green tokens divided by the total number of tokens:

\frac{10}{40}

, which reduces to

\frac{1}{4}

.

Adım Adım Çözüm

1

Determine the total number of tokens in the box.

Total tokens =

40

Since

16

red tokens represent a probability of

\frac{2}{5}

, we can find the total by dividing the part by its fraction:

16 \div \frac{2}{5} = 16 \times \frac{5}{2} = 40

.

2

Calculate the number of green tokens.

Green tokens =

10

Subtract the known red and blue tokens from the total:

40 - 16 \text{ (red)} - 14 \text{ (blue)} = 10 \text{ green tokens}

.

3

Calculate the probability of drawing a green token.

Probability =

\frac{1}{4}

Probability is the number of favorable outcomes divided by total outcomes:

\frac{10}{40}

, which simplifies to

\frac{1}{4}

.

Anahtar Kavram

Single Event Probability and Total Outcomes

Soru 835Soru →

An electrical technician wants to reduce the electrical resistance of a standard copper wire run without changing the metal type or operating temperature. Which of the following modifications will decrease the resistance of the wire?

Increasing the total length of the wire

Increasing the cross-sectional area of the wire

Operating the wire at a significantly elevated temperature

Selecting a wire with a smaller circular diameter

Cevabı ve açıklamayı göster

Cevap: Increasing the cross-sectional area of the wire

Cevap

Increasing the cross-sectional area of the wire decreases its electrical resistance.

Electrical resistance in a conductor is inversely proportional to its cross-sectional area (

R = \rho \frac{L}{A}

). Increasing the thickness or cross-sectional area provides more conductive pathways for free electrons, thereby lowering the total resistance.

Adım Adım Çözüm

1

Recall the fundamental physical relationship between conductor dimensions and electrical resistance

R = \rho \frac{L}{A}

, where

R

is resistance,

\rho

is material resistivity,

L

is conductor length, and

A

is cross-sectional area

This formula defines how physical geometry directly influences opposition to electron flow.

2

Analyze how changing the cross-sectional area (

A

) impacts resistance (

R

)

Because cross-sectional area (

A

) is in the denominator, resistance is inversely proportional to area (

R \propto \frac{1}{A}

)

Increasing the area (

A

) reduces the calculated resistance (

R

), allowing electrons to flow more easily.

Anahtar Kavram

Physical factors governing conductor resistance

Tahmini Süre:45s

Soru 836Soru →

A $100\text{ k}\Omega$ linear potentiometer is connected across a $12\text{ V}$ DC power supply, with terminal 1 connected to $+12\text{ V}$ , terminal 3 connected to ground ( $0\text{ V}$ ), and terminal 2 serving as the adjustable wiper. If the wiper is set to $40\%$ of its total travel distance away from terminal 3 toward terminal 1, what is the output voltage measured at terminal 2 relative to ground, and what is the resistance between terminal 1 and terminal 2?

7.2\text{ V}

and

40\text{ k}\Omega

4.8\text{ V}

and

60\text{ k}\Omega

4.8\text{ V}

and

40\text{ k}\Omega

4.8\text{ V}

and

600\ \Omega

Cevabı ve açıklamayı göster

Cevap: $4.8\text{ V}$ and $60\text{ k}\Omega$

Cevap

4.8\text{ V}

output voltage and

60\text{ k}\Omega

resistance between terminal 1 and terminal 2

A linear potentiometer configured across a DC voltage source acts as a continuous voltage divider. With terminal 3 connected to ground (

0\text{ V}

) and the wiper at

40\%

travel from ground, the lower resistance segment

R_{2-3}

is

40\text{ k}\Omega

, yielding an output voltage of

V_{\text{out}} = 12\text{ V} \times (40\text{ k}\Omega / 100\text{ k}\Omega) = 4.8\text{ V}

. The upper resistance segment between terminal 1 (

+12\text{ V}

) and terminal 2 (wiper) is the remaining portion:

100\text{ k}\Omega - 40\text{ k}\Omega = 60\text{ k}\Omega

.

Adım Adım Çözüm

1

Calculate the resistance of the lower track section between terminal 2 (wiper) and terminal 3 (ground).

R_{2-3} = 0.40 \times 100\text{ k}\Omega = 40\text{ k}\Omega

The wiper is positioned at

40\%

of total travel measured from the ground terminal.

2

Calculate the output voltage

V_{\text{out}}

at terminal 2 relative to ground using the voltage divider relationship.

V_{\text{out}} = V_{\text{in}} \times \left(\frac{R_{2-3}}{R_{\text{total}}}\right) = 12\text{ V} \times \left(\frac{40\text{ k}\Omega}{100\text{ k}\Omega}\right) = 4.8\text{ V}

A potentiometer connected across a voltage source functions as an adjustable voltage divider.

3

Determine the remaining resistance between terminal 1 (

+12\text{ V}

) and terminal 2 (wiper).

R_{1-2} = R_{\text{total}} - R_{2-3} = 100\text{ k}\Omega - 40\text{ k}\Omega = 60\text{ k}\Omega

The total resistance is divided into two series segments by the wiper contact.

Anahtar Kavram

Potentiometer voltage division and wiper segment resistance distribution

Tahmini Süre:45s

Soru 837Soru →

A logistics officer is analyzing data from various base operations. Match each statistical description on the left with its correctly calculated value on the right.

Soldaki öğeye tıklayın, sonra eşleşen sağdaki öğeye tıklayın

Cevabı ve açıklamayı göster

Cevap

The mean crate weight matches with 50, the median supply request matches with 16.5, the missing shipment for a target mean matches with 31, and the mode of repair times matches with 4.

Each pairing correctly applies the fundamental rules of mean, median, mode, and algebraic representation of statistical targets. The calculations strictly follow the rules for measures of central tendency.

Adım Adım Çözüm

1

Calculate the mean for the first description.

(45 + 60 + 55 + 40 + 50) / 5 = 50

The mean is the arithmetic average of a data set.

2

Calculate the median for the second description.

Sorted list:

12, 14, 15, 18, 20, 22

. Average of middle two:

(15 + 18) / 2 = 16.5

The median is the middle value of an ordered set, or the average of the two middle values for an even number of items.

3

Calculate the missing value for the third description.

125 - (20 + 24 + 28 + 22) = 31

The sum of all values must equal the target mean multiplied by the total number of values.

4

Identify the mode for the fourth description.

The number

4

appears three times.

The mode is the most frequent value in a data set.

Anahtar Kavram

Measures of Central Tendency

Soru 838Soru →

Two standard silicon rectifier diodes are arranged in a dual-input diode OR logic configuration. The anode of Diode 1 is connected to a $+5.0\text{ V}$ DC supply, and the anode of Diode 2 is connected to a $+2.0\text{ V}$ DC supply. Both cathodes connect to a common junction that ties to ground through a $2.2\text{ k}\Omega$ load resistor. Assuming each forward-biased silicon diode exhibits a nominal barrier potential drop of $0.7\text{ V}$ , what is the resulting output voltage measured at the common cathode junction?

1.3\text{ V}

4.3\text{ V}

5.0\text{ V}

6.3\text{ V}

Cevabı ve açıklamayı göster

Cevap: $4.3\text{ V}$

Cevap

The voltage measured at the common output cathode junction is

4.3\text{ V}

.

The output potential is determined by the diode with the highest anode voltage. Diode 1 has

+5.0\text{ V}

applied to its anode, which forward-biases its PN junction and establishes a common cathode potential of

5.0\text{ V} - 0.7\text{ V} = 4.3\text{ V}

. Because Diode 2 has only

+2.0\text{ V}

at its anode while its cathode is held at

+4.3\text{ V}

, it experiences a net reverse bias of

-2.3\text{ V}

and remains completely non-conductive (OFF).

Adım Adım Çözüm

1

Determine which diode enters forward conduction first by comparing anode potentials.

Diode 1 has an anode voltage of

+5.0\text{ V}

, which is higher than Diode 2's anode voltage of

+2.0\text{ V}

.

In a common-cathode configuration, the diode with the most positive anode potential forward-biases first and sets the output voltage.

2

Calculate the output node voltage established by the conducting diode.

V_{\text{out}} = 5.0\text{ V} - 0.7\text{ V} = 4.3\text{ V}

.

A conducting silicon diode drops approximately

0.7\text{ V}

across its PN junction.

3

Evaluate the biasing state of Diode 2 with the cathode node established at

4.3\text{ V}

.

V_{\text{anode2}} - V_{\text{cathode}} = 2.0\text{ V} - 4.3\text{ V} = -2.3\text{ V}

(Reverse Biased / OFF).

Because the cathode is more positive than the anode, Diode 2 is reverse-biased, acts as an open circuit, and contributes no current to the load.

Anahtar Kavram

Diode conduction states, forward barrier potential drop, and reverse-bias isolation in multi-diode circuits

Tahmini Süre:1m 30s

Soru 839Soru →

An electrical technician connects a $12\text{ V}$ DC battery across the primary winding of an iron-core transformer through a switch. After the switch is closed and a steady current is established in the primary winding, what voltage behavior is observed across the secondary winding?

A continuous

12\text{ V}

DC output is maintained as long as primary current flows.

A continuous alternating voltage is generated across the secondary terminals.

A brief voltage pulse occurs when the switch closes, followed by zero output while current remains steady.

A constant electrostatic charge accumulates in the core without producing any transient voltage.

Cevabı ve açıklamayı göster

Cevap: A brief voltage pulse occurs when the switch closes, followed by zero output while current remains steady.

Cevap

A brief voltage pulse occurs when the switch closes, followed by zero output while current remains steady.

According to Faraday's Law of Electromagnetic Induction, an electromotive force (voltage) is induced in a secondary winding only when there is a changing magnetic flux (

e = -N \frac{\Delta \Phi}{\Delta t}

). When the switch is initially closed, the current rises from zero to its maximum level, generating an expanding magnetic field that induces a brief voltage pulse. Once the DC current reaches a steady state, the magnetic field stops changing (

\frac{\Delta \Phi}{\Delta t} = 0

), causing the induced secondary voltage to drop immediately to zero.

Adım Adım Çözüm

1

Analyze the conditions required for electromagnetic induction according to Faraday's Law.

Induced voltage is directly proportional to the rate of change of magnetic flux (

e = -N \frac{\Delta \Phi}{\Delta t}

).

A magnetic field must be expanding, collapsing, or moving relative to a conductor to induce an electromotive force (EMF).

2

Determine the magnetic flux behavior during switch closure versus steady DC state.

During switch closure, current rises from

0\text{ A}

to steady state, creating a rapidly expanding magnetic field (brief voltage pulse). Once steady state is reached, current is constant, making

\frac{\Delta \Phi}{\Delta t} = 0

, resulting in zero induced secondary voltage.

Steady direct current produces a stationary, unchanging magnetic field that cannot induce voltage in a stationary secondary coil.

Anahtar Kavram

Faraday's Law of Electromagnetic Induction and Transformer Operation

Tahmini Süre:1m 0s

Soru 840Soru →

A direct-current (DC) ventilation blower operates on a $28\text{ V}$ aircraft electrical bus and draws a steady current of $5\text{ A}$ . How many watts ( $\text{W}$ ) of electrical power are consumed by the blower?

Cevabı ve açıklamayı göster

Cevap: 140

Cevap

The power consumed by the blower is

140\text{ W}

.

According to Watt's Law, electrical power (

P

) dissipated by a direct-current device equals the product of the applied voltage (

V

) and the current (

I

). Multiplying

28\text{ V}

by

5\text{ A}

gives

140\text{ W}

.

Adım Adım Çözüm

1

Identify the known electrical quantities given in the scenario.

Voltage

V = 28\text{ V}

and Current

I = 5\text{ A}

.

Identifying the known parameters determines which form of Watt's Law to use.

2

Apply the fundamental Watt's Law formula for electrical power (

P = V \times I

).

P = 28\text{ V} \times 5\text{ A} = 140\text{ W}

.

Electrical power in a direct-current circuit is calculated by multiplying the potential difference across the load by the current flowing through it.

Anahtar Kavram

Watt's Law for DC Power (

P = V \times I

)

Tahmini Süre:45s

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