Question

a torch bulb is rated 5volt and 500mA. calculate the 1.power 2.resistance 3.energy consumed when it is lighted for 4 hours??​

Answer 1

Answer:

This means that the bulb works when a voltage of 5V is applied across it and 500mA of current flows through it. Hence, the power dissipated across the torch bulb is equal to 2.5W . Hence, the resistance of the bulb is equal to 10Ω . Hence, the energy consumed by the bulb is equal to 36kJ .

Answer 2

Given

Potential difference =V=5V

Current =I= 500mA=500x/1000 A=0.5 A

I) Power = V X I

= 5x0.5 =5x5/10=2.5 W

II)Reistance =R=?

By Ohm's law: V=IR

R=V/I

R=5/0.5

=50/5 =10 ohms

III)Energy consumed when it is lighted for 4 hours

Energy =Power x time

t=4hrs=4x60x60

=2.5x 4x60x60

=36000joules/sec