Power. Energy conservation and efficiency
Answers are for parents and teachers.
1
A = 2400 J, t = 8 s. N (W)?
300
2
A 500 W motor does how much work in 20 s (J)?
10000
3
A_useful = 240 J, A_total = 300 J. η (%)?
80
4
For one home appliance (lamp, iron, mixer), write the energy conversions (use appliances only with an adult).
For example: a light bulb — electric energy → light and heat.
5
Why should you never touch electrical appliances with wet hands?
Electric current can pass through wet hands; use electricity only with adult supervision.