Question

The current flowing at the instant of switching of a 40w lamp to a 240v supply is 2a. Resistance

temperature coefficient of filament material is 0.0055/°c at room temperature of(20+rn)°c.

calculate the working temperature of the filament and current taken during normal working

conditions

Answer 1

Answer:

Hey buddy,

◆ Answer-

R0 = 36 ohm

◆ Explanation-

# Given-

P = 100 W

V = 240 V

R = 16 R0

# Solution-

At operating temperature, Power of the bulb is calculated by -

P = V^2 / R

R = V^2 / P

Substituting values -

R = 240^2 / 100

R = 576 ohm

Resistance at room temprature is given by-

R0 = R/16

R0 = 576/16

R0 = 36 ohm

Resistance of the lamp at room temperature is 36 ohm.

Hope this helps...