Question

A torch bulb is rated 4V and 200mA calculate its a) resistance b) power,and c)energy consumedwhen it is lughted for 6 hours

Answer 1

Explanation:

(a)

resistance R = V/i by ohms law

here V in Volts , i in amp

convert 200 mA = 0.2 Amp.

R = 4 / 0.2 =20 ohms

(b) power P = Vxi = 4x0.2 =0.8 wats

(c) energy in 6 hrs E= Pxt = 0.8x6 = 4.8 wat hrs.