Current Electricity Charging Discharging Of Capacitors Question 118
Question: A thermocouple of resistance $ 1.6,\Omega $ is connected in series with a galvanometer of $ 8,\Omega $ resistance. The thermocouple develops and e.m.f. of $ 10\mu V $ per degree temperature difference between two junctions. When one junction is kept at $ 0^{o}C $ and the other in a molten metal, the galvanometer reads 8 millivolt. The temperature of molten metal, when e.m.f. varies linearly with temperature difference, will be
Options:
A) $ 960^{o}C $
B) $ 1050^{o}C $
C) $ 1275^{o}C $
D) $ 1545^{o}C $
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Answer:
Correct Answer: A
Solution:
Let the temperature of molten metal is $ t^{o}C. $ The thermo-emf $ e=10\times {{10}^{-6}}tvolt $ Current in the circuit $ i=\frac{e}{R+R _{G}}=\frac{{{10}^{-5}}t}{8+1.6}=\frac{{{10}^{-5}}t}{9.6},amp. $ But $ i=\frac{V}{R _{G}}=\frac{8\times {{10}^{-3}}}{8} $ \ $ \frac{{{10}^{-5}}t}{9.6}=\frac{8\times {{10}^{-3}}}{8} $ or $ t=\frac{9.6\times {{10}^{-3}}}{{{10}^{-5}}}=960^{o}C $
BETA
