The energy transferred in an electric circuit is given by which expression?

• A. E = I V t
• B. E = V I t
• C. E = V / I t
• D. E = I / V t

Answer: (A)

Energy transferred equals the power delivered over a period of time. In an electrical circuit, power is the rate at which energy is used or transferred, and it equals voltage times current, P = V × I. Multiplying by the time the circuit operates gives the total energy transferred: E = P × t = V × I × t. Since multiplication commutes, E = I × V × t is the same expression. The other options don’t match this form and would not give the correct units for energy.