Printable Worksheet
Use this sheet after the Electricity and Light lesson. It focuses on energy conversion, the visible spectrum, and how kitchen appliances turn electrical energy into radiation.
1. In one sentence, what does an incandescent bulb do with most of its electrical energy?
2. What does an induction hob actually heat — its own surface, the pan, or the food directly?
3. Why does a piece of fruit look red under a red light source but much darker under a blue one?
Choose one of these and explain it using the ideas from the Electricity and Light lesson:
— a toaster element glowing orange during use
— a kitchen light making food look different from how it looks in daylight
— an induction hob staying cool to the touch while the pan above it becomes very hot
An incandescent bulb and an LED both produce roughly the same visible light output. The LED uses about one-fifth of the electrical energy. Where does the rest of the energy go in the incandescent bulb? Try to account for all of it.
4. A kettle on a 230 V supply draws A. What is its power in kilowatts? (P = V×I)
5. The same kettle runs for seconds. How much energy does it use, in kilojoules? (E = P×t)