First slide

Electrical power

Question

Two electric bulbs have tungsten filament of same length. If one of them gives 60 watt and other 100 watt, then

Easy

A

100 watt bulb has thicker filament
B

60 watt bulb has thicker filament
C

both filaments are of same thickness
D

it is impossible to get different wattage unless the lengths are different

Solution

$R \propto \frac{1}{P}$
Hence resistance of 60 watt bulb will be more than resistance of 100 watt bulb
Further $R = ρ (\frac{1}{{πr}^{2}}) or R \propto \frac{1}{r^{2}}$
So, the radius of 1o0 watt bulb will be more than 60 watt bulb, Hence 100 watt bulb has thicker filament.

Get Instant Solutions

When in doubt download our app. Now available Google Play Store- Doubts App

Recieve an sms with download link

Doubts App

OR

SCAN ME

Doubts App

Doubts App