Question

an electric glow lamp is rated 240 V 60w find in joules the heat produced when the lamp is switched on for 4 second. Plz answer

Answer 1

Explanation:

Given :

power =p=100w

voltage=220V

time=2hrs

Resistance=R=?

Formula to be used :

P=V*I

BUT I=V/R

∴P=V²/R

⇒R=V²/P

=220x220/100

=484ohms

To calculate Energy consumed :

Formula : E=Pxt

=100x5

=500Wh

=500/1000 kWh

0.5 kWh

∴ Resistance while glowing is 484 ohms and energy consumed in kWh per day ps 0.5

Answer 2

Answer:

P = VI.

60 = 220 x I,

I = 60 / 220,

I = 0.273A.

V = IR.

220 = 0.273 x R

R = 220 / 0.273

R = 805.86ohms