### JEE Main On 16 April 2018 Question 2

##### Question: A heating element has a resistance of $ 100\Omega $ at room temperature. When it is connected to a supply of 220V, a steady current of 2A passes in it and temperature is $ 500^{o}C $ more than room temperature. What is the temperature coefficient of resistance of the heating element? [JEE Main 16-4-2018]

#### Options:

A) $ 1\times {10^{-4}}{{,}^{o}}{C^{-1}} $

B) $ 5\times {10^{-4}}{{,}^{o}}{C^{-1}} $

C) $ 2\times {10^{-4}}{{,}^{o}}{C^{-1}} $

D) $ 0.5\times {10^{-4}}{{,}^{o}}{C^{-1}} $

## Show Answer

#### Answer:

Correct Answer: C

#### Solution:

We know that resistance $ R=\frac{V}{i}=\frac{220}{2}=R _{o}(1+\alpha \Delta t) $

Also $ R _{o} $ is given as $ 100\Omega $

Putting $ \Delta T=500,K $ We get $ \alpha =2\times {10^{-4}} $