Q

If a wire is stretched to make it 0.1% longer, its resistance will

• Option 1)

• Option 2)

• Option 3)

• Option 4)

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S solutionqc
Answered Nov 11, 2018

As we have learned

Ratio of resistances -

If length is given

$R$ $\alpha$ $l^{2}$

- wherein

$\frac{R_{1}}{R_{2}}=\left (\frac{l_{1}}{l_{2}} \right )^{2}$

$lA = constant \\A = \frac{K}{l}$

$R = \frac{\rho l}{A } = \rho \frac{l }{K/l }= \frac{\rho }{K }l^2$

$l= l_0 + (0.001 l)\\R' = \frac{\rho }{K}l_0^2 [ 1+0.001]^2 = R_0 [1+0.002]$

R increases by 0.2 %

Option 1)

Option 2)

Option 3)

Option 4)

If $\Theta _{i}$  is the inversion temperature , $\Theta _{n}$ is the neutral temperature , $\Theta _{c}$  is the temperature of the cold junction, then

• Option 1)

$\Theta _{i}+\Theta _{c}=\Theta _{n}$

• Option 2)

$\Theta _{i}-\Theta _{c}=2\Theta _{n}$

• Option 3)

$\frac{\Theta _{i}+\Theta _{c}}{2}=\Theta _{n}$

• Option 4)

$\Theta _{c}-\Theta _{i}=2\Theta _{n}$

View All (1) Answers

A Avinash
Answered Jul 07, 2018

$\Theta _{c}+\Theta _{i} = 2\Theta _{n}$

$\Rightarrow \Theta _{n} = \frac{\Theta _{c}+\Theta _{i}}{2}$

Option 1)

$\Theta _{i}+\Theta _{c}=\Theta _{n}$

This option is incorrect.

Option 2)

$\Theta _{i}-\Theta _{c}=2\Theta _{n}$

This option is incorrect.

Option 3)

$\frac{\Theta _{i}+\Theta _{c}}{2}=\Theta _{n}$

This option is correct.

Option 4)

$\Theta _{c}-\Theta _{i}=2\Theta _{n}$

This option is incorrect.

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