Question

A electic toaster of resistance 20 ohm takes a current of 5a. calculate the heat developed in 30 s. a bulb is rated at 5v,100a.calculate its power & resistance.

Answer 1

R = 20 ohm
i = 5A
t = 30s

$h = i {}^{2} rt$

$h = 5 {}^{2} \times 20 \times 30$

$h = 15000j$

Heat developed by heater is 15000 j.

V = 5v
i = 100 A

R = V / i = 5 / 100

R = 0.05 ohm

Resistance of bulb is 0.05 ohms

P = V i
= 5 × 100
= 500w

Power of bulb is 500 w.


Thanks