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Question

Difficulty: EasyOhm's Law

A portable electric heater is connected to a 120 V120\text{ V} direct-current power supply. If the heating element has an internal resistance of 24 Ω24\ \Omega, what is the current flowing through the circuit?

  1. A
    0.2 A0.2\text{ A}
  2. 5 A5\text{ A}Answer
  3. C
    50 A50\text{ A}
  4. D
    2880 A2{}880\text{ A}

Answer

5 A5\text{ A}
Using Ohm's Law (I=VRI = \frac{V}{R}), dividing the applied voltage of 120 V120\text{ V} by the resistance of 24 Ω24\ \Omega yields exactly 5 A5\text{ A}.

Step-by-Step Solution

1
Identify the known values and state Ohm's Law formula for current.
Voltage V=120 VV = 120\text{ V}, Resistance R=24 ΩR = 24\ \Omega, Formula: I=VRI = \frac{V}{R}
Ohm's Law states that current is directly proportional to voltage and inversely proportional to resistance.
2
Substitute the circuit values into the formula and solve for current (II).
I=120 V24 Ω=5 AI = \frac{120\text{ V}}{24\ \Omega} = 5\text{ A}
Dividing 120120 by 2424 computes the magnitude of current flow in amperes.

Key Concept

Ohm's Law expresses the fundamental relationship among voltage, current, and resistance (I=V/RI = V / R).
Estimated Time:45s
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Topics

Ohm's Law

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