Question

A 40 W lamp turns half the electrical energy to give light. How much light energy does it give out in 10
seconds​

Answer 1

• Power=P=40W
• Time=t=10s

Here Heat energy is produced.

$\boxed{H=Pt}$

$\\ \sf\longmapsto H=40(10)$

$\\ \sf\longmapsto H=400J$