Current Electricity Charging Discharging Of Capacitors Question 392
Question: The resistance of a conductor is 5 ohm at 50oC and 6 ohm at 100oC. Its resistance at 0oC is
[KCET 2000]
Options:
A) 1 ohm
B) 2 ohm
C) 3 ohm
D) 4 ohm
Show Answer
Answer:
Correct Answer: D
Solution:
$ \frac{R _{1}}{R _{2}}=\frac{(1+\alpha t _{1})}{(1+\alpha t _{2})}\Rightarrow \frac{5}{6}=\frac{(1+\alpha \times 50)}{(1+\alpha \times 100)} $
$ \Rightarrow \alpha =\frac{1}{200}\text{ per}{{}^{o}}C $ Again by $ R _{t}=R _{0}(1+\alpha t) $
$ \Rightarrow 5=R _{0}( 1+\frac{1}{200}\times 50 )\Rightarrow R _{0}=4\Omega . $
BETA
