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The resistance of hot tungsten filament ...

The resistance of hot tungsten filament is about 10 times the cold resistance. What will be the resistance of 100 W and 200 V lamp when not in use?

A

`14,000 Omega`

B

`400 Omega`

C

`40 Omega`

D

`4 Omega`

Text Solution

Verified by Experts

The correct Answer is:
C
When hot , `R = (V^(2))/( P) = ( 200 xx 200)/( 100) = 400 omega`
Hence, when cold, the resistance is `40 Omega`.
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