A charge of 10 C is transferred across a potential difference of 220 V. Determine the work done.

Analyze the question: We are given a charge (Q = 10 C) moved across a potential difference (V = 220 V), and we need the work done (W).

Concept: Potential difference is defined as the work done per unit charge:

V = W / Q

so

W = Q × V

Solution:

W = Q × V W = 10 C × 220 V W = 2200 J

Checking the options:

• A. 22 J: this would come from dividing 220 by 10 (V ÷ Q), which is the wrong operation.
• B. 2200 J: matches our working.
• C. 210 J: this would come from adding 10 and 200, which has no basis in the formula.
• D. 230 J: this would come from adding 10 and 220, which is also wrong.

Tip: Remember the units: 1 volt = 1 joule per coulomb (1 V = 1 J/C). So multiply volts by coulombs to get joules. A good memory aid is "W = QV", similar to "Work = Quantity × Voltage". Avoid dividing here, since that is the trap behind option A.