Question 702: Current Electricity

Question

The temperature coefficient of the resistance of a wire is 0.00125 per $${ }^{\circ} \mathrm{C}$$. At $$300 \mathrm{~K}$$ its resistance is $$1 \Omega$$. The resistance of wire will be $$2 \Omega$$ at

Accepted Answer

Note None of the four options are correct, through option (d) is close to correct answer.
$$\begin{aligned}
R_t & =R_0(1+\alpha t) \
1 & =R_0(1+0.00125 	imes 27) \quad 	ext{.... (i)}\
2 & =R_0(1+0.00125 	imes t) \quad 	ext{.... (ii)}\end{aligned}$$
From Eqs. (i) and (ii)
$$t=848^{\circ} \mathrm{C}=1121 \mathrm{~K}$$

Answer

1154 K

Answer

1100 K

Answer

1400 K

Answer

1121 K

Current Electricity

The temperature coefficient of the resistance of a wire is 0.00125 per ${ }^{\circ} \mathrm{C}. At 300 \mathrm{~K} its resistance is 1 \Omega. The resistance of wire will be 2 \Omega$ at

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