Home
Class 12
PHYSICS
The resistance of a field coil measures ...

The resistance of a field coil measures ` 50 Omega` at ` 20^@ C` and `65 Omega at 70^@ C`. Find the temperature coefficient of resistance.

Text Solution

Verified by Experts

`R_(20) = 50 Omega, 70^@ C, R_(70) = 65 Omega, alpha = ? `
` R_t = R_0 = (1 + alpha t)`
`R_20 = R_0 (1+ alpha 20)`
` 50 = R_0 (1 + alpha 20 )`
` 50 = R_0 (1 + alpha 20 ) " …(1)"`
`R_70 = R_0 (1+alpha 70)`
` 65 = R_0 (1+ alpha 70)" ...(2)"`
Dividing (2) by (1)
`65/50 = (1 + 70 alpha)/(1 + 20 alpha)`
` 65 + 1300 alpha = 50 + 3500 alpha `
`2200 alpha = 15`
`alpha = (0.00 68)/(""^(@)C)`
` = 0.0068 //^@ C`
Promotional Banner

Similar Questions

Explore conceptually related problems

Define temperature coefficient or resistance.

The temperature coefficient of resistance of alloys is:

A wire has resistance of 2.0 Omega at 25^@ C and 2.5 Omega at 100^@ C . Calculate the temperature coefficient of resistance of the wire.

The temperature coefficient of resistance is positive _______

The resistance of a bulb filament is 100 Omega at a temperature of 100^@C . If its temperature coefficient of resistance be 0.005 per ^@C , then its resistance will become 200 Omega at a temperature:

A silver wire has a resistance of 2.1 Omega 27.5^(@)C Omega and a resistance of 2.7Omega "at" 100^(@)C . Determinethe temperature co-efficient of resistance of the silver.

Resistance of a material at 10^(@)C and 40^(@)C are 45Omega and 85Omega respectively. Find its temperature co-efficient of resistance