Tüm alıştırma soruları

1526 soru

Soru 1501Soru

A sealed rigid glass bulb contains a fixed mass of helium gas at an initial pressure of 1.20×105 Pa1.20 \times 10^5\text{ Pa} and a temperature of 27C27^\circ\text{C}. Assuming the volume of the bulb remains constant, calculate the final pressure of the gas in Pa\text{Pa} when it is heated to 127C127^\circ\text{C}.

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Cevap: 160000

Cevap

The final pressure of the gas is 1.60×105 Pa1.60 \times 10^5\text{ Pa} (160000 Pa160\,000\text{ Pa}).
The correct result of 160000 Pa160\,000\text{ Pa} (1.60×105 Pa1.60 \times 10^5\text{ Pa}) is obtained by applying the Pressure Law P1T1=P2T2\frac{P_1}{T_1} = \frac{P_2}{T_2} using absolute temperatures (T1=300 KT_1 = 300\text{ K}, T2=400 KT_2 = 400\text{ K}).

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1
Convert the initial and final temperatures from degrees Celsius to the absolute temperature scale (Kelvin).
T1=27+273=300 KT_1 = 27 + 273 = 300\text{ K} and T2=127+273=400 KT_2 = 127 + 273 = 400\text{ K}.
All gas law equations require absolute temperatures in Kelvin.
2
Apply the Pressure Law (Gay-Lussac's Law) for a fixed mass of gas at constant volume.
P1T1=P2T2    P2=P1×T2T1\frac{P_1}{T_1} = \frac{P_2}{T_2} \implies P_2 = P_1 \times \frac{T_2}{T_1}
The pressure of a gas is directly proportional to its absolute temperature when volume remains constant.
3
Substitute the known values to find P2P_2.
P2=1.20×105 Pa×400 K300 K=1.60×105 Pa=160000 PaP_2 = 1.20 \times 10^5\text{ Pa} \times \frac{400\text{ K}}{300\text{ K}} = 1.60 \times 10^5\text{ Pa} = 160\,000\text{ Pa}.
Multiplying 1.20×1051.20 \times 10^5 by the temperature ratio 43\frac{4}{3} gives 1.60×105 Pa1.60 \times 10^5\text{ Pa}.

Anahtar Kavram

Pressure Law (Gay-Lussac's Law) and absolute temperature conversion
Soru 1502Soru

A rigid container AA of volume 0.060 m30.060\text{ m}^3 contains an ideal gas at an absolute pressure of 4.50×105 Pa4.50 \times 10^5\text{ Pa} and a temperature of 27C27^\circ\text{C}. Container AA is connected via a narrow tube of negligible volume with a valve to an evacuated rigid container BB of volume 0.040 m30.040\text{ m}^3. The valve is opened, allowing gas to flow between the containers until equilibrium is established. If container AA is maintained at 27C27^\circ\text{C} while container BB is maintained at 127C127^\circ\text{C}, what is the final equilibrium pressure of the gas in kilopascals (kPa)?

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Cevap: 300

Cevap

300 kPa
Converting both temperatures to Kelvin (300 K300\text{ K} and 400 K400\text{ K}) and applying mole conservation (ntotal=nA+nBn_{\text{total}} = n_A + n_B) yields a final uniform pressure of 3.00×105 Pa3.00 \times 10^5\text{ Pa}, which equals 300 kPa300\text{ kPa}.

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1
Convert temperatures from degrees Celsius to kelvins.
TA=27C+273=300 KT_A = 27^\circ\text{C} + 273 = 300\text{ K} and TB=127C+273=400 KT_B = 127^\circ\text{C} + 273 = 400\text{ K}.
Gas laws and calculations using the ideal gas equation require absolute temperatures in Kelvin.
2
Calculate the initial number of moles of gas present in the system.
ntotal=pAVARTA=(4.50×105 Pa)(0.060 m3)R(300 K)=90Rn_{\text{total}} = \frac{p_A V_A}{R T_A} = \frac{(4.50 \times 10^5\text{ Pa})(0.060\text{ m}^3)}{R(300\text{ K})} = \frac{90}{R}.
Container B is initially evacuated, meaning all gas molecules originate from container A.
3
Express the total number of moles at final equilibrium in terms of final pressure PP.
nfinal=nA+nB=PVARTA+PVBRTB=PR(0.060300+0.040400)=PR(2.0×104+1.0×104)=3.0×104PRn_{\text{final}} = n_A + n_B = \frac{P V_A}{R T_A} + \frac{P V_B}{R T_B} = \frac{P}{R} \left(\frac{0.060}{300} + \frac{0.040}{400}\right) = \frac{P}{R} (2.0 \times 10^{-4} + 1.0 \times 10^{-4}) = \frac{3.0 \times 10^{-4} P}{R}.
At equilibrium, the pressure PP becomes uniform throughout both interconnected containers.
4
Equate the initial and final total moles to solve for the equilibrium pressure PP.
90R=3.0×104PR    P=903.0×104=3.00×105 Pa=300 kPa\frac{90}{R} = \frac{3.0 \times 10^{-4} P}{R} \implies P = \frac{90}{3.0 \times 10^{-4}} = 3.00 \times 10^5\text{ Pa} = 300\text{ kPa}.
The total mass and number of moles of gas are conserved within the sealed system.

Anahtar Kavram

Conservation of total moles in interconnected gas containers governed by the ideal gas equation PV=nRTPV = nRT
Tahmini Süre:2m 30s
Soru 1503Soru

An air bubble with an initial volume of 4.0 cm34.0\text{ cm}^3 is released by a scuba diver at a depth where the total pressure is 2.50×105 Pa2.50 \times 10^5\text{ Pa} and the water temperature is 7C7^\circ\text{C}. Calculate the volume of the bubble, in cm3\text{cm}^3, just as it reaches the surface where the pressure is 1.00×105 Pa1.00 \times 10^5\text{ Pa} and the water temperature is 77C77^\circ\text{C}.

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Cevap: 12.5

Cevap

12.5 cm³
Converting temperatures to the Kelvin scale (T1=280 KT_1 = 280\text{ K} and T2=350 KT_2 = 350\text{ K}) and applying the combined gas law formula P1V1T1=P2V2T2\frac{P_1 V_1}{T_1} = \frac{P_2 V_2}{T_2} gives a final volume of 12.5 cm312.5\text{ cm}^3.

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1
Convert the initial and final temperatures from degrees Celsius to absolute temperatures in Kelvin.
T1=7C+273=280 KT_1 = 7^\circ\text{C} + 273 = 280\text{ K} and T2=77C+273=350 KT_2 = 77^\circ\text{C} + 273 = 350\text{ K}.
Gas law calculations require thermodynamic temperature measured on the Kelvin scale.
2
Set up the combined gas law relationship for a fixed mass of gas.
P1V1T1=P2V2T2\frac{P_1 V_1}{T_1} = \frac{P_2 V_2}{T_2}
The mass of air inside the bubble remains constant while pressure, volume, and temperature change simultaneously.
3
Substitute the known values into the equation and solve for the final volume V2V_2.
V2=P1V1T2P2T1=(2.50×105 Pa)×(4.0 cm3)×(350 K)(1.00×105 Pa)×(280 K)=12.5 cm3V_2 = \frac{P_1 V_1 T_2}{P_2 T_1} = \frac{(2.50 \times 10^5\text{ Pa}) \times (4.0\text{ cm}^3) \times (350\text{ K})}{(1.00 \times 10^5\text{ Pa}) \times (280\text{ K})} = 12.5\text{ cm}^3.
Algebraic substitution yields the correct final volume of the expanded bubble.

Anahtar Kavram

Combined Gas Law
Soru 1504Soru

A transverse progressive wave traveling along a taut string is represented by the equation y(x,t)=0.04sin(200t8x)y(x, t) = 0.04 \sin(200t - 8x), where xx and yy are measured in meters and tt is in seconds. What is the maximum transverse speed of a particle on the string in meters per second?

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Cevap: 8

Cevap

The maximum transverse speed of a particle on the string is 8.0 m/s8.0\text{ m/s}.
The maximum speed of a particle executing simple harmonic motion as part of a progressive wave is given by vp,max=Aωv_{p,\text{max}} = A\omega. From the wave equation y(x,t)=0.04sin(200t8x)y(x, t) = 0.04 \sin(200t - 8x), the amplitude is A=0.04 mA = 0.04\text{ m} and the angular frequency is ω=200 rad/s\omega = 200\text{ rad/s}. Multiplying these values yields vp,max=0.04×200=8.0 m/sv_{p,\text{max}} = 0.04 \times 200 = 8.0\text{ m/s}.

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1
Compare the given wave displacement equation with the standard progressive wave form.
Standard form: y(x,t)=Asin(ωtkx)y(x, t) = A \sin(\omega t - kx). Matching coefficients gives A=0.04 mA = 0.04\text{ m}, ω=200 rad/s\omega = 200\text{ rad/s}, and k=8 rad/mk = 8\text{ rad/m}.
Extracting amplitude and angular frequency is essential for evaluating particle motion.
2
Differentiate displacement with respect to time to find the expression for particle velocity.
vp(x,t)=yt=Aωcos(ωtkx)v_p(x, t) = \frac{\partial y}{\partial t} = A \omega \cos(\omega t - kx).
Particle velocity represents the time rate of change of transverse displacement.
3
Determine maximum particle speed by setting the magnitude of the cosine factor to 1.
vp,max=Aω=0.04 m×200 rad/s=8.0 m/sv_{p,\text{max}} = A \omega = 0.04 \text{ m} \times 200 \text{ rad/s} = 8.0 \text{ m/s}.
The maximum absolute value of the cosine function is 1.

Anahtar Kavram

Maximum particle velocity in a progressive wave (vp,max=Aωv_{p,\text{max}} = A\omega)
Tahmini Süre:1m 30s
Soru 1505Soru

A container made of a metal with a linear expansivity of 2.0×105 K12.0 \times 10^{-5}\text{ K}^{-1} has a volume of 1000 cm31000\text{ cm}^3 at 20C20^\circ\text{C}. It is completely filled with a liquid at this temperature. When the system is heated to 120C120^\circ\text{C}, 40 cm340\text{ cm}^3 of the liquid overflows. If the real cubic expansivity of the liquid is expressed as X×104 K1X \times 10^{-4}\text{ K}^{-1}, what is the value of XX?

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Cevap: 4.6

Cevap

The value of XX is 4.6.
The real cubic expansivity of a liquid is given by γr=γa+γv\gamma_r = \gamma_a + \gamma_v. Calculating apparent expansivity gives γa=401000×100=4.0×104 K1\gamma_a = \frac{40}{1000 \times 100} = 4.0 \times 10^{-4}\text{ K}^{-1}. The vessel's volume expansivity is γv=3×2.0×105=0.6×104 K1\gamma_v = 3 \times 2.0 \times 10^{-5} = 0.6 \times 10^{-4}\text{ K}^{-1}. Adding them together yields γr=4.6×104 K1\gamma_r = 4.6 \times 10^{-4}\text{ K}^{-1}, so X=4.6X = 4.6.

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1
Calculate the temperature change ΔT\Delta T
\Delta T = 120^\circ\text{C} - 20^\circ\text{C} = 100\text{ K}
The thermal expansion is driven by the change in temperature.
2
Calculate the apparent cubic expansivity γa\gamma_a
\gamma_a = \frac{40\text{ cm}^3}{1000\text{ cm}^3 \times 100\text{ K}} = 4.0 \times 10^{-4}\text{ K}^{-1}
Apparent expansivity is defined as the fraction of initial volume overflowed per degree rise in temperature.
3
Calculate the volume expansivity of the container γv\gamma_v
\gamma_v = 3\alpha = 3 \times (2.0 \times 10^{-5}\text{ K}^{-1}) = 6.0 \times 10^{-5}\text{ K}^{-1} = 0.6 \times 10^{-4}\text{ K}^{-1}
Cubic expansivity of an isotropic solid container is three times its linear expansivity.
4
Sum apparent expansivity and vessel cubic expansivity to find real cubic expansivity γr\gamma_r
\gamma_r = \gamma_a + \gamma_v = 4.0 \times 10^{-4} + 0.6 \times 10^{-4} = 4.6 \times 10^{-4}\text{ K}^{-1}
Real expansivity accounts for both the apparent expansion of the liquid and the expansion of the container.

Anahtar Kavram

Relationship between real cubic expansivity, apparent cubic expansivity, and vessel expansivity
Soru 1506Soru

An X-ray tube operates at an accelerating potential difference of 25.0 kV25.0\text{ kV}. Calculate the maximum frequency of the emitted X-ray radiation in units of 1018 Hz10^{18}\text{ Hz}. (Take Planck's constant h=6.63×1034 Jsh = 6.63 \times 10^{-34}\text{ J}\cdot\text{s} and elementary charge e=1.60×1019 Ce = 1.60 \times 10^{-19}\text{ C}).

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Cevap: 6.03

Cevap

The maximum frequency of the emitted X-rays is 6.03×1018 Hz6.03 \times 10^{18}\text{ Hz}, which gives a value of 6.036.03 in units of 1018 Hz10^{18}\text{ Hz}.
The maximum frequency of X-ray photons emitted occurs when an accelerating electron transfers all of its kinetic energy (eVe V) into a single photon (hfmaxh f_{\text{max}}). Substituting e=1.60×1019 Ce = 1.60 \times 10^{-19}\text{ C}, V=25,000 VV = 25,000\text{ V}, and h=6.63×1034 Jsh = 6.63 \times 10^{-34}\text{ J}\cdot\text{s} gives fmax=6.03×1018 Hzf_{\text{max}} = 6.03 \times 10^{18}\text{ Hz}, which equals 6.036.03 in the requested unit of 1018 Hz10^{18}\text{ Hz}.

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1
Convert potential difference from kilovolts to volts
V=25.0 kV=25,000 VV = 25.0\text{ kV} = 25,000\text{ V}
Standard SI units are required for calculations.
2
Determine maximum kinetic energy of the incident electrons
Emax=eV=1.60×1019 C×25,000 V=4.00×1015 JE_{\text{max}} = e V = 1.60 \times 10^{-19}\text{ C} \times 25,000\text{ V} = 4.00 \times 10^{-15}\text{ J}
The maximum photon energy produced equals the full kinetic energy acquired by an accelerated electron.
3
Calculate maximum frequency fmaxf_{\text{max}} using Duane-Hunt relation
fmax=Emaxh=4.00×1015 J6.63×1034 Js6.03×1018 Hzf_{\text{max}} = \frac{E_{\text{max}}}{h} = \frac{4.00 \times 10^{-15}\text{ J}}{6.63 \times 10^{-34}\text{ J}\cdot\text{s}} \approx 6.03 \times 10^{18}\text{ Hz}
According to the Duane-Hunt law, eV=hfmaxe V = h f_{\text{max}}.

Anahtar Kavram

Duane-Hunt Law and Maximum X-ray Frequency
Soru 1507Soru

The threshold wavelength for photoelectric emission from a metallic surface is 500 nm500\text{ nm}. What is the work function of the metal in electron-volts (eV\text{eV})? [Take Planck's constant h=6.6×1034 J sh = 6.6 \times 10^{-34}\text{ J s}, speed of light c=3.0×108 m s1c = 3.0 \times 10^{8}\text{ m s}^{-1}, and 1 eV=1.6×1019 J1\text{ eV} = 1.6 \times 10^{-19}\text{ J}]

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Cevap: 2.48

Cevap

The work function of the metal is 2.48 eV2.48\text{ eV} (or 2.475 eV2.475\text{ eV}).
The work function W0W_0 is calculated using W0=hcλ0W_0 = \frac{hc}{\lambda_0}. Substituting h=6.6×1034 J sh = 6.6 \times 10^{-34}\text{ J s}, c=3.0×108 m s1c = 3.0 \times 10^8\text{ m s}^{-1}, and λ0=500×109 m\lambda_0 = 500 \times 10^{-9}\text{ m} gives W0=3.96×1019 JW_0 = 3.96 \times 10^{-19}\text{ J}. Converting to electron-volts yields 3.96×10191.6×1019=2.475 eV\frac{3.96 \times 10^{-19}}{1.6 \times 10^{-19}} = 2.475\text{ eV}, which rounds to 2.48 eV2.48\text{ eV}.

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1
State the relationship between work function and threshold wavelength
W0=hcλ0W_0 = \frac{hc}{\lambda_0}
The work function is the minimum energy required to liberate an electron, which corresponds to the maximum wavelength (threshold wavelength λ0\lambda_0) that can cause emission.
2
Substitute the physical constants and threshold wavelength to calculate W0W_0 in joules
W0=6.6×1034×3.0×108500×109=3.96×1019 JW_0 = \frac{6.6 \times 10^{-34} \times 3.0 \times 10^{8}}{500 \times 10^{-9}} = 3.96 \times 10^{-19}\text{ J}
Evaluating hc/λ0hc / \lambda_0 yields the work function energy in standard SI units (Joules).
3
Convert the calculated work function into electron-volts
W0=3.96×10191.6×1019=2.475 eVW_0 = \frac{3.96 \times 10^{-19}}{1.6 \times 10^{-19}} = 2.475\text{ eV}
Dividing the energy in Joules by 1.6×1019 J/eV1.6 \times 10^{-19}\text{ J/eV} converts the value to electron-volts.

Anahtar Kavram

Work Function and Threshold Wavelength Relationship
Soru 1508Soru

The dynamic pressure PP exerted by a moving fluid depends on its density ρ\rho and flow velocity vv according to the relationship P=kρavbP = k \rho^a v^b, where kk is a dimensionless constant. What is the value of the exponent bb?

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Cevap: 2

Cevap

The value of the exponent bb is 2.
Equating the exponent of time (T) on both sides of the dimensional equation M L1T2=MaL3a+bTb\text{M L}^{-1} \text{T}^{-2} = \text{M}^a \text{L}^{-3a + b} \text{T}^{-b} yields 2=b-2 = -b, giving b=2b = 2.

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1
Determine the base dimensions of all physical quantities in the equation.
Pressure [P]=M L1T2[P] = \text{M L}^{-1} \text{T}^{-2}, Density [ρ]=M L3[\rho] = \text{M L}^{-3}, and Velocity [v]=L T1[v] = \text{L T}^{-1}.
Dimensional analysis requires converting derived physical quantities into fundamental dimensions of Mass (M), Length (L), and Time (T).
2
Apply dimensional homogeneity by substituting the dimensions into P=kρavbP = k \rho^a v^b.
\text{M L}^{-1} \text{T}^{-2} = \text{M}^a \text{L}^{-3a + b} \text{T}^{-b}
The principle of dimensional homogeneity states that exponents of M, L, and T must match on both sides of a physically correct equation.
3
Equate the corresponding exponents for time (T) and solve for bb.
-2 = -b \implies b = 2
Matching the powers of T directly yields the numerical value of exponent bb.

Anahtar Kavram

Principle of Dimensional Homogeneity and Dimensional Analysis
Soru 1509Soru

A rectangular metallic sheet with a linear expansivity of 1.8×105 K11.8 \times 10^{-5}\text{ K}^{-1} experiences a temperature rise of 50 K50\text{ K}. If the increase in its surface area is 0.90 cm20.90\text{ cm}^2, what was the initial surface area of the sheet in cm2\text{cm}^2?

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Cevap: 500

Cevap

The initial surface area of the metallic sheet is 500 cm2500\text{ cm}^2.
The initial area is found by converting linear expansivity to area expansivity (\beta = 2\alpha = 3.6 \times 10^{-5}\text{ K}^{-1}) and substituting into the area expansion relation \Delta A = A_0 \beta \Delta T, giving A_0 = \frac{0.90}{3.6 \times 10^{-5} \times 50} = 500\text{ cm}^2$.

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1
Calculate the area (superficial) expansivity (\beta)
\beta = 2\alpha = 2 \times 1.8 \times 10^{-5}\text{ K}^{-1} = 3.6 \times 10^{-5}\text{ K}^{-1}
Surface area expansion depends on area expansivity, which is twice the linear expansivity for an isotropic solid.
2
Formulate the thermal area expansion equation
\Delta A = A_0 \beta \Delta T
The fractional change in area is directly proportional to the area expansivity and the temperature change.
3
Rearrange the formula to solve for the initial surface area (A_0)
A_0 = \frac{\Delta A}{\beta \Delta T}
Isolating the required unknown quantity.
4
Substitute the known numerical values and compute
A_0 = \frac{0.90\text{ cm}^2}{(3.6 \times 10^{-5}\text{ K}^{-1})(50\text{ K})} = \frac{0.90}{1.8 \times 10^{-3}} = 500\text{ cm}^2
Evaluating the expression yields the exact initial surface area.

Anahtar Kavram

Relationship between Linear Expansivity and Area Expansivity

Alternatif Yöntem

Calculate fractional area expansion per kelvin: \beta = 2\alpha = 3.6 \times 10^{-5}\text{ K}^{-1}.Totalfractionalexpansionfor. Total fractional expansion for 50\text{ K}is is 3.6 \times 10^{-5} \times 50 = 0.0018 .Theninitialarea. Then initial area A_0 = \frac{0.90}{0.0018} = 500\text{ cm}^2$.
Tahmini Süre:1m 30s
Soru 1510Soru

At a coastal meteorological station in Calabar, air temperature observations recorded at four specific intervals during a 24-hour cycle were 22.0C22.0^\circ\text{C}, 31.5C31.5^\circ\text{C}, 28.5C28.5^\circ\text{C}, and 24.0C24.0^\circ\text{C}. What is the mean temperature of these observations in C^\circ\text{C}?

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Cevap: 26.5

Cevap

The mean temperature computed from the four observations is 26.5C26.5^\circ\text{C}.
The mean temperature is calculated by summing all recorded values (22.0+31.5+28.5+24.0=106.0C22.0 + 31.5 + 28.5 + 24.0 = 106.0^\circ\text{C}) and dividing by the total number of observations (44), resulting in 26.5C26.5^\circ\text{C}.

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1
Sum all four temperature values taken across the observation periods.
The total sum is 22.0C+31.5C+28.5C+24.0C=106.0C22.0^\circ\text{C} + 31.5^\circ\text{C} + 28.5^\circ\text{C} + 24.0^\circ\text{C} = 106.0^\circ\text{C}.
Finding the arithmetic mean requires calculating the aggregate total of all recorded temperature data points.
2
Divide the calculated aggregate sum by the count of observation intervals.
106.0C4=26.5C\frac{106.0^\circ\text{C}}{4} = 26.5^\circ\text{C}.
Dividing the sum by the sample size (44) yields the average temperature across the recorded intervals.

Anahtar Kavram

Calculation of mean temperature from periodic daily observations
Tahmini Süre:1m 30s
Soru 1511Soru

A sealed cylinder in an industrial pneumatic lift contains 0.080 m30.080\text{ m}^3 of gas at an initial pressure of 1.50×105 Pa1.50 \times 10^5\text{ Pa} and a temperature of 27C27^\circ\text{C}. The piston compresses the gas to a final volume of 0.020 m30.020\text{ m}^3, raising the pressure to 7.50×105 Pa7.50 \times 10^5\text{ Pa}. What is the final temperature of the gas in degrees Celsius (C^\circ\text{C})?

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Cevap: 102

Cevap

The final temperature of the gas is 102C102^\circ\text{C}.
Using the combined gas law P1V1T1=P2V2T2\frac{P_1 V_1}{T_1} = \frac{P_2 V_2}{T_2} with absolute initial temperature T1=300 KT_1 = 300\text{ K} gives T2=375 KT_2 = 375\text{ K}. Subtracting 273273 yields the final temperature of 102C102^\circ\text{C}.

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1
Convert initial temperature to absolute temperature (Kelvin)
T1=27+273=300 KT_1 = 27 + 273 = 300\text{ K}
Gas laws require thermodynamic temperature measured on the Kelvin scale.
2
Set up the Combined Gas Law equation
P1V1T1=P2V2T2\frac{P_1 V_1}{T_1} = \frac{P_2 V_2}{T_2}
Relates initial and final states when pressure, volume, and temperature all change for a fixed mass of gas.
3
Calculate the final absolute temperature T2T_2
T2=300×7.50×105×0.0201.50×105×0.080=375 KT_2 = 300 \times \frac{7.50 \times 10^5 \times 0.020}{1.50 \times 10^5 \times 0.080} = 375\text{ K}
Evaluating the ratio of P2V2P_2 V_2 to P1V1P_1 V_1 yields 1.251.25.
4
Convert final temperature from Kelvin to Celsius
θ2=375273=102C\theta_2 = 375 - 273 = 102^\circ\text{C}
The question explicitly requires the answer in degrees Celsius.

Anahtar Kavram

Combined Gas Law and thermodynamic temperature conversion
Soru 1512Soru

An aluminum electric cable suspended between two transmission poles has a length of 100 m100\text{ m} at an initial morning temperature of 20C20^\circ\text{C}. By afternoon, the cable temperature increases to 50C50^\circ\text{C}. Given that the linear expansivity of aluminum is 2.3×105 K12.3 \times 10^{-5}\text{ K}^{-1}, what is the increase in the length of the cable in centimeters?

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Cevap: 6.9

Cevap

The increase in the length of the cable is 6.9 cm6.9\text{ cm}.
Applying the formula for linear expansion ΔL=L0αΔT\Delta L = L_0 \alpha \Delta T, where L0=100 mL_0 = 100\text{ m}, α=2.3×105 K1\alpha = 2.3 \times 10^{-5}\text{ K}^{-1}, and ΔT=30 K\Delta T = 30\text{ K}, gives ΔL=0.069 m\Delta L = 0.069\text{ m}. Converting this to centimeters yields 6.9 cm6.9\text{ cm}.

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1
Determine the temperature change
\Delta T = 30\text{ K}
Temperature change is the difference between final and initial temperatures: 50C20C=30 K50^\circ\text{C} - 20^\circ\text{C} = 30\text{ K}.
2
Calculate expansion in meters using the linear expansivity formula
\Delta L = 0.069\text{ m}
\Delta L = L_0 \alpha \Delta T = 100 \times (2.3 \times 10^{-5}) \times 30 = 0.069\text{ m}.
3
Convert the change in length to centimeters
\Delta L = 6.9\text{ cm}
Since 1 m=100 cm1\text{ m} = 100\text{ cm}, multiply 0.069 m0.069\text{ m} by 100100 to obtain 6.9 cm6.9\text{ cm}.

Anahtar Kavram

Linear expansivity of solid conductors
Tahmini Süre:1m 30s
Soru 1513Soru

A glass flask of volume 800 cm3800\text{ cm}^3 at 10C10^\circ\text{C} is completely filled with a liquid having a real volume expansivity of 5.0×104 K15.0 \times 10^{-4}\text{ K}^{-1}. If the linear expansivity of the glass is 1.0×105 K11.0 \times 10^{-5}\text{ K}^{-1}, what volume of the liquid (in cm3\text{cm}^3) will overflow when the flask and its contents are heated to 60C60^\circ\text{C}?

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Cevap: 18.8

Cevap

18.8 cm^3
The volume of liquid that overflows is equal to the apparent increase in volume of the liquid. The apparent volume expansivity of the liquid \(\gamma_a\) is given by \(\gamma_a = \gamma_r - \gamma_v\), where \(\gamma_r = 5.0 \times 10^{-4}\text{ K}^{-1}\) is the real expansivity of the liquid, and \(\gamma_v = 3\alpha = 3 \times 1.0 \times 10^{-5} = 0.3 \times 10^{-4}\text{ K}^{-1}\) is the volume expansivity of the glass flask. Therefore, \(\gamma_a = 5.0 \times 10^{-4} - 0.3 \times 10^{-4} = 4.7 \times 10^{-4}\text{ K}^{-1}\). The overflow volume is \(\Delta V_a = V_0 \times \gamma_a \times \Delta T = 800 \times (4.7 \times 10^{-4}) \times 50 = 18.8\text{ cm}^3\).

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1
Calculate the cubic expansivity of the glass flask
\(\gamma_v = 3.0 \times 10^{-5}\text{ K}^{-1} = 0.3 \times 10^{-4}\text{ K}^{-1}\)
The volume expansivity of a solid container is three times its linear expansivity (\(\gamma_v = 3\alpha\)).
2
Determine the apparent volume expansivity of the liquid
\(\gamma_a = 4.7 \times 10^{-4}\text{ K}^{-1}\)
Apparent expansivity is equal to real expansivity minus the vessel cubic expansivity (\(\gamma_a = \gamma_r - \gamma_v\)).
3
Calculate the change in temperature
\(\Delta T = 50\text{ K}\)
The temperature increases from 10C10^\circ\text{C} to 60C60^\circ\text{C}.
4
Calculate the overflow volume
\(\Delta V_a = 18.8\text{ cm}^3\)
The overflow volume is the apparent expansion of the liquid given by \(\Delta V_a = V_0 \gamma_a \Delta T\).

Anahtar Kavram

Real and apparent cubic expansivity of liquids
Soru 1514Soru

A geography student constructs a pie chart to illustrate the annual export earnings of agricultural commodities from a region. The total value of all exports is $480 million\text{\$}480\text{ million}, with oil palm products accounting for $108 million\text{\$}108\text{ million}. What is the central angle, in degrees, of the sector representing oil palm products?

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Cevap: 81

Cevap

The central angle of the sector representing oil palm products is 8181^\circ.
The correct answer is obtained by finding the component share of the total value (108 / 480 = 0.225) and multiplying by 360 degrees, yielding an angle of 81 degrees.

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1
Calculate the fractional proportion of the specific component relative to the total data value
108480=0.225\frac{108}{480} = 0.225
A sector in a pie chart represents a fractional part of the total statistical value.
2
Convert the calculated proportion into degrees of a circle
0.225×360=810.225 \times 360^\circ = 81^\circ
A full pie chart circle contains 360360^\circ, so multiplying the component proportion by 360360^\circ gives its angular representation.

Anahtar Kavram

Calculating Sector Angles in Pie Charts
Soru 1515Soru

A cell of electromotive force EE and internal resistance rr supplies a current of 1.2 A1.2\text{ A} when connected across a 4.0 Ω4.0\ \Omega resistor. When this resistor is replaced with a 10.0 Ω10.0\ \Omega resistor, the current decreases to 0.6 A0.6\text{ A}. Calculate the internal resistance rr of the cell in ohms (Ω\Omega).

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Cevap: 2

Cevap

The internal resistance of the cell is 2.0 Ω2.0\ \Omega.
For a complete circuit, the electromotive force EE is related to load resistance RR, internal resistance rr, and current II by E=I(R+r)E = I(R + r). Setting up equations for both load conditions gives E=1.2(4.0+r)E = 1.2(4.0 + r) and E=0.6(10.0+r)E = 0.6(10.0 + r). Equating these expressions yields 4.8+1.2r=6.0+0.6r4.8 + 1.2r = 6.0 + 0.6r, which simplifies to 0.6r=1.20.6r = 1.2, giving an internal resistance of r=2.0 Ωr = 2.0\ \Omega.

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1
Formulate the circuit equation for the first load resistance
E=1.2×(4.0+r)=4.8+1.2rE = 1.2 \times (4.0 + r) = 4.8 + 1.2r
Using Ohm's law for a complete circuit, the electromotive force equals current times total circuit resistance: E=I(R1+r)E = I(R_1 + r).
2
Formulate the circuit equation for the second load resistance
E=0.6×(10.0+r)=6.0+0.6rE = 0.6 \times (10.0 + r) = 6.0 + 0.6r
The cell maintains the same internal electromotive force EE and internal resistance rr with the new load resistor R2R_2.
3
Equate the expressions for EE and solve for rr
4.8+1.2r=6.0+0.6r    0.6r=1.2    r=2.0 Ω4.8 + 1.2r = 6.0 + 0.6r \implies 0.6r = 1.2 \implies r = 2.0\ \Omega
Since EE is constant for the cell, setting the two right-hand sides equal yields a single linear equation for the unknown internal resistance rr.

Anahtar Kavram

Electromotive Force and Internal Resistance
Soru 1516Soru

An object is launched vertically upward from the ground with an initial velocity of 40 m/s40\text{ m/s}. At the exact same instant, a second object is dropped from rest from a height of 100 m100\text{ m} directly above the first object. Taking the acceleration due to gravity g=10 m/s2g = 10\text{ m/s}^2, at what time (in seconds) after launch will the two objects meet?

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Cevap: 2.5

Cevap

The two objects meet after 2.5 seconds.
Because both objects experience identical downward gravitational acceleration (g=10 m/s2g = 10\text{ m/s}^2), their relative acceleration is zero. The relative velocity between them remains constant at 40 m/s40\text{ m/s}. The time to cover the initial separation distance of 100 m100\text{ m} is calculated directly as t=distancerelative velocity=10040=2.5 st = \frac{\text{distance}}{\text{relative velocity}} = \frac{100}{40} = 2.5\text{ s}.

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1
Set up the position-time equations for both objects taking ground level as y=0 my = 0\text{ m}.
For the upward-launched object: y1(t)=ut12gt2=40t5t2y_1(t) = u t - \frac{1}{2}gt^2 = 40t - 5t^2. For the dropped object: y2(t)=h012gt2=1005t2y_2(t) = h_0 - \frac{1}{2}gt^2 = 100 - 5t^2.
Kinematic equations of motion under uniform gravitational acceleration apply to both bodies.
2
Equate the two vertical position equations to solve for the meeting time tt.
40t5t2=1005t2    40t=10040t - 5t^2 = 100 - 5t^2 \implies 40t = 100
When the objects meet, they share the exact same vertical position y1(t)=y2(t)y_1(t) = y_2(t) at time tt.
3
Calculate the value of tt.
t=10040=2.5 st = \frac{100}{40} = 2.5\text{ s}
Direct algebraic division yields the time elapsed before collision/meeting.

Anahtar Kavram

Relative vertical motion under uniform gravity
Tahmini Süre:1m 30s
Soru 1517Soru

In an industrial non-destructive testing setup, an X-ray tube produces continuous X-radiation with a minimum cut-off wavelength of 3.3×1011 m3.3 \times 10^{-11}\text{ m}. What is the operating accelerating potential difference of the tube in kilovolts (kV\text{kV})? (Take Planck's constant h=6.6×1034 J sh = 6.6 \times 10^{-34}\text{ J s}, speed of light c=3.0×108 m s1c = 3.0 \times 10^8\text{ m s}^{-1}, and electron charge e=1.6×1019 Ce = 1.6 \times 10^{-19}\text{ C}).

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Cevap: 37.5

Cevap

The operating accelerating potential difference of the tube is 37.5 kV.
According to the Duane-Hunt law, the maximum kinetic energy of electrons hitting the target equal the maximum photon energy produced: eV=hfmax=hcλmine V = h f_{\text{max}} = \frac{h c}{\lambda_{\text{min}}}. Rearranging to solve for voltage gives V=hceλminV = \frac{h c}{e \lambda_{\text{min}}}. Substituting h=6.6×1034 J sh = 6.6 \times 10^{-34}\text{ J s}, c=3.0×108 m s1c = 3.0 \times 10^8\text{ m s}^{-1}, e=1.6×1019 Ce = 1.6 \times 10^{-19}\text{ C}, and λmin=3.3×1011 m\lambda_{\text{min}} = 3.3 \times 10^{-11}\text{ m} yields V=37,500 VV = 37,500\text{ V}, which equals 37.5 kV37.5\text{ kV}.

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1
Relate the maximum electron kinetic energy to the shortest X-ray photon wavelength using Duane-Hunt law
eV=Emax=hcλmine V = E_{\text{max}} = \frac{h c}{\lambda_{\text{min}}}
At the Duane-Hunt cutoff limit, the entire kinetic energy of an accelerating electron is converted into a single X-ray photon.
2
Rearrange the equation to solve for the accelerating voltage VV
V=hceλminV = \frac{h c}{e \lambda_{\text{min}}}
Isolating VV allows direct calculation from known fundamental constants and the given minimum wavelength.
3
Substitute the physical constants and calculate the value of VV in Volts
V=(6.6×1034 J s)(3.0×108 m s1)(1.6×1019 C)(3.3×1011 m)=37,500 VV = \frac{(6.6 \times 10^{-34}\text{ J s})(3.0 \times 10^8\text{ m s}^{-1})}{(1.6 \times 10^{-19}\text{ C})(3.3 \times 10^{-11}\text{ m})} = 37,500\text{ V}
Carrying out arithmetic with scientific notation powers yields 3.75×104 V3.75 \times 10^4\text{ V}.
4
Convert the potential difference from Volts (V) to kilovolts (kV)
37,500 V=37.5 kV37,500\text{ V} = 37.5\text{ kV}
Dividing by 1000 converts potential difference into the requested kilovolt unit.

Anahtar Kavram

Duane-Hunt Law and Cut-off Wavelength in X-ray Production
Soru 1518Soru

An atom has three stationary energy levels given by E1=12.50 eVE_1 = -12.50\text{ eV}, E2=6.80 eVE_2 = -6.80\text{ eV}, and E3=3.50 eVE_3 = -3.50\text{ eV}. What is the wavelength, in nanometers (nm\text{nm}), of the photon emitted during the transition that produces the longest wavelength line in its emission spectrum? (Take Planck's constant h=6.6×1034 Jsh = 6.6 \times 10^{-34}\text{ J}\cdot\text{s}, speed of light c=3.0×108 m/sc = 3.0 \times 10^8\text{ m/s}, and 1 eV=1.6×1019 J1\text{ eV} = 1.6 \times 10^{-19}\text{ J})

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Cevap: 375

Cevap

The wavelength of the photon emitted for the longest wavelength spectral line is 375 nm.
Photon wavelength is related to transition energy by λ=hcΔE\lambda = \frac{hc}{\Delta E}. To find the longest wavelength spectral line, the transition with the smallest energy gap must be used. Evaluating all emission transitions between the levels gives ΔE32=3.30 eV\Delta E_{3 \to 2} = 3.30\text{ eV}, ΔE21=5.70 eV\Delta E_{2 \to 1} = 5.70\text{ eV}, and ΔE31=9.00 eV\Delta E_{3 \to 1} = 9.00\text{ eV}. The minimum energy difference is 3.30 eV3.30\text{ eV}. Converting 3.30 eV3.30\text{ eV} to Joules gives 3.30×1.6×1019=5.28×1019 J3.30 \times 1.6 \times 10^{-19} = 5.28 \times 10^{-19}\text{ J}. Substituting this into the wavelength formula yields λ=6.6×1034×3.0×1085.28×1019=3.75×107 m=375 nm\lambda = \frac{6.6 \times 10^{-34} \times 3.0 \times 10^8}{5.28 \times 10^{-19}} = 3.75 \times 10^{-7}\text{ m} = 375\text{ nm}.

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1
Determine which electronic transition yields the longest wavelength photon.
Transition from E3E_3 to E2E_2 yields the minimum energy difference of 3.30 eV3.30\text{ eV}.
Since λ=hcΔE\lambda = \frac{hc}{\Delta E}, the longest wavelength corresponds to the smallest energy transition.
2
Convert the transition energy from electron-volts to Joules.
ΔE=5.28×1019 J\Delta E = 5.28 \times 10^{-19}\text{ J}.
SI units are required for calculations involving Planck's constant and the speed of light.
3
Calculate the wavelength λ\lambda using the photon energy formula λ=hcΔE\lambda = \frac{hc}{\Delta E}.
λ=375 nm\lambda = 375\text{ nm}.
Substituting h=6.6×1034 Jsh = 6.6 \times 10^{-34}\text{ J}\cdot\text{s}, c=3.0×108 m/sc = 3.0 \times 10^8\text{ m/s}, and ΔE=5.28×1019 J\Delta E = 5.28 \times 10^{-19}\text{ J} gives 3.75×107 m3.75 \times 10^{-7}\text{ m}, which equals 375 nm375\text{ nm}.

Anahtar Kavram

Inverse relationship between transition energy and photon wavelength in atomic emission spectra
Soru 1519Soru

A sand bag of mass 8.0 kg8.0\text{ kg} is suspended vertically by a light rope. A projectile of mass 0.50 kg0.50\text{ kg} moving horizontally at a speed of 170 m s1170\text{ m s}^{-1} strikes the sand bag and becomes embedded in it. What is the common speed, in m s1\text{m s}^{-1}, of the sand bag and the embedded projectile immediately after collision?

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Cevap: 10

Cevap

The common speed of the sand bag and embedded projectile immediately after the collision is 10.0 m s110.0\text{ m s}^{-1}.
According to the principle of conservation of linear momentum, total momentum before impact equals total momentum after impact. The initial momentum of the system is entirely from the projectile: pi=0.50×170=85 kg m s1p_i = 0.50 \times 170 = 85\text{ kg m s}^{-1}. After collision, both objects move together with a total mass of 0.50+8.0=8.5 kg0.50 + 8.0 = 8.5\text{ kg}. Setting 8.5v=858.5 v = 85 gives v=10 m s1v = 10\text{ m s}^{-1}.

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1
State the conservation of linear momentum equation for an inelastic collision
m1u1+m2u2=(m1+m2)vm_1 u_1 + m_2 u_2 = (m_1 + m_2) v
Since no net external horizontal force acts on the system during impact, total linear momentum is conserved.
2
Substitute the given values into the momentum balance equation
(0.50 kg)(170 m s1)+(8.0 kg)(0 m s1)=(0.50 kg+8.0 kg)v(0.50\text{ kg})(170\text{ m s}^{-1}) + (8.0\text{ kg})(0\text{ m s}^{-1}) = (0.50\text{ kg} + 8.0\text{ kg}) v
The projectile embeds into the sand bag, so they move together with a single combined mass.
3
Solve the linear equation for the common final velocity vv
85=8.5v    v=10 m s185 = 8.5 v \implies v = 10\text{ m s}^{-1}
Dividing total initial momentum by total combined mass yields the final speed.

Anahtar Kavram

Conservation of Linear Momentum in Completely Inelastic Collisions
Tahmini Süre:1m 30s
Soru 1520Soru

A particle traveling along a straight line accelerates uniformly from an initial speed uu to a final speed of 25 m/s25\text{ m/s} over a distance of 150 m150\text{ m} in a time duration of 8 s8\text{ s}. What is the initial speed uu in m/s\text{m/s}?

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Cevap: 12.5

Cevap

The initial speed of the particle is 12.5 m/s12.5\text{ m/s}.
Under uniform acceleration, displacement is given by the product of average velocity and time: s=u+v2ts = \frac{u + v}{2}t. Substituting s=150 ms = 150\text{ m}, v=25 m/sv = 25\text{ m/s}, and t=8 st = 8\text{ s} gives 150=4(u+25)150 = 4(u + 25), which yields u=12.5 m/su = 12.5\text{ m/s}.

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1
Identify the given parameters and select the appropriate kinematic equation.
Givens: s=150 ms = 150\text{ m}, v=25 m/sv = 25\text{ m/s}, t=8 st = 8\text{ s}. Formula: s=u+v2ts = \frac{u + v}{2}t.
This formula relates displacement directly to average velocity and time under uniform acceleration without needing the acceleration variable.
2
Substitute the given values into the formula.
150=(u+252)×8=4(u+25)150 = \left(\frac{u + 25}{2}\right) \times 8 = 4(u + 25).
Simplifying 82\frac{8}{2} gives a factor of 44 multiplying (u+25)(u + 25).
3
Isolate and solve for the unknown initial speed uu.
u+25=1504=37.5    u=12.5 m/su + 25 = \frac{150}{4} = 37.5 \implies u = 12.5\text{ m/s}.
Subtracting 2525 from 37.537.5 yields the value of uu.

Anahtar Kavram

Kinematics with uniform linear acceleration
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