A charge of 5.0 C passes through a resistor, transferring 40 J of electrical energy to the resistor as it does so. What is the potential difference across the resistor?

Answer: B. Step 1: Recall the relationship between p.d. energy and charge Potential difference is the energy transferred per unit charge: V = W/Q Step 2: Substitute the values The energy transferred is W = 40 J and the charge is Q = 5.0 C: V = 40 J/5…

Electric Circuits and Resistance: Question 5

Syllabus 4.2.3

Multiple choice Core 1 mark

A charge of $5.0\text{ C}$ passes through a resistor, transferring $40\text{ J}$ of electrical energy to the resistor as it does so. What is the potential difference across the resistor?

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Step 1: Recall the relationship between p.d. energy and charge

Potential difference is the energy transferred per unit charge:

$V = \frac{W}{Q}$

Step 2: Substitute the values

The energy transferred is $W = 40\text{ J}$ and the charge is $Q = 5.0\text{ C}$ :

$V = \frac{40\text{ J}}{5.0\text{ C}}$

Step 3: Work out the potential difference

$V = 8.0\text{ V}$

Why the other options are wrong

Option	How it arises	Error
$0.125\text{ V}$	$5.0 \div 40$	Formula inverted (charge ÷ energy)
$45\text{ V}$	$40 + 5.0$	Added instead of dividing
$200\text{ V}$	$40 \times 5.0$	Multiplied instead of dividing

Final answers

Potential difference $= \boxed{8.0\text{ V}}$ , option B