Calculating Electric Energy Flashcards

All 5 cards in this deck

What is the equation linking energy transferred, charge moved and potential difference?

energy transferred (J) = charge moved (C) × potential difference (V), $E = Q \times V$

What is the equation linking energy transferred, current, potential difference and time?

energy transferred (J) = current (A) × potential difference (V) × time (s), $E = I \times V \times t$

What are the steps to find the energy transferred by a supply from the charge moved?

e.g. a charge of $5\,\mathrm{C}$ moves through a $6\,\mathrm{V}$ supply

1. Write $E = Q \times V$
2. Substitute: $E = 5 \times 6$
3. Energy transferred $= 30\,\mathrm{J}$

What are the steps to find the energy transferred by a component from current, p.d. and time?

e.g. $2\,\mathrm{A}$ at $12\,\mathrm{V}$ for $10\,\mathrm{s}$

1. Write $E = I \times V \times t$
2. Substitute with time in seconds: $E = 2 \times 12 \times 10$
3. Energy transferred $= 240\,\mathrm{J}$

True or false? For a given charge, a higher potential difference means more energy is transferred.

True. $E = Q \times V$, so energy is proportional to p.d.