Question

aA lamp consume 500 joule of electrical energy in 20 sec.what is power of lamp? also find electrical energy consume in uits if lamp operates for 2 hours daily for 15 days?

Answer 1

Given that,
Electrical energy, E=500 J
Time, t=20 seconds
$$\begin{gathered} \mathrm{E}=\mathrm{P}\times \mathrm{t} \\ \mathrm{Or}\mathrm{P}=\frac{\mathrm{E}}{\mathrm{t}} \\ \mathrm{or}\mathrm{P}=\frac{500}{20}=25\mathrm{W} \\ \mathrm{Now},\mathrm{according}\mathrm{to}\mathrm{the}\mathrm{second}\mathrm{condition}, \\ \mathrm{Energy}\mathrm{consumed}\mathrm{in}15\mathrm{days},\mathrm{E}=\mathrm{P}\times \mathrm{t} \\ =25\times [2\times 60\times 60]\times 15 \\ =2700\mathrm{kJ} \end{gathered}$$