Question

An electric bulb is rated 3V and 750 mA. Calculate its :
(a) Power
(b) Energy consumed by the bulb when lighted for 30 mins.

Answer 1

Dear student,

An electric bulb is rated 3V and 750 mA means volatge and current rating is given,


$$\begin{gathered} GivenV=3V \\ andI=750mA \\ 1.power=P=VI=3\times \frac{750}{1000}=2.25W \\ 2.Energyfor30minutei.e.for\frac{1}{2}hours(or\frac{1}{2}hours=\frac{1}{2}\times 60\times 60sec) \\ E=P\times t=2.25\times \frac{1}{2}=1.125Wh \\ orE=P\times t=2.25\times \frac{1}{2}\times 60\times 60=4050J \end{gathered}$$

Regards,