Current Electricity Charging Discharging Of Capacitors Question 376
Question: A platinum resistance thermometer has a resistance of $ 50,\Omega $ at $ 20{}^\circ C $ . When dipped in a liquid the resistance becomes $ 76.8,\Omega $ . The temperature coefficient of resistance for platinum is $ \alpha =3.92\times {{10}^{-3}}/{}^\circ C $ . The temperature of the liquid is
Options:
A) $ 100{}^\circ C $
B) $ 137{}^\circ C $
C) $ 167{}^\circ C $
D) $ 200{}^\circ C $
Show Answer
Answer:
Correct Answer: C
Solution:
$ \frac{R _{1}}{R _{2}}=\frac{(1+\alpha t _{1})}{(1+\alpha t _{2})}\Rightarrow \frac{50}{76.8}=\frac{(1+3.92\times {{10}^{-3}}\times 20)}{(1+3.92\times {{10}^{-3}}t)} $
$ \Rightarrow t=167{}^\circ C $
BETA
