Question

A battery of e.m.f 12V supplies a current of 5A for 2 minutes. How much energy is supplied in this time?

Answer 1

From this formula e.m.f.

$$\epsilon=\frac{A}{q}$$

we have

$$A=q\cdot\epsilon=It\epsilon$$

where

$$I=5 (A); t=120 (s); \epsilon=12(V)$$ $$A=5\cdot120\cdot12=7200 (J)$$