A 100 W bulb operates for 10 s. Calculate electrical energy transferred.

Solution & explanation

1. Given power 100 W and time 10 s.

2. A watt is one joule each second.

3. Use energy = power × time.

   $$E=P\times t$$

4. Insert values.

   $$E=100\times 10$$

5. Multiply.

   $$E=1000$$

6. This is total electrical energy; a bulb transfers it as heat and light.

E = 1000 J