A) \[8.5\times {{10}^{-3}}/K\]
B) \[3.5\times {{10}^{-3}}/K\]
C) \[0.5\times {{10}^{-3}}/K\]
D) \[5\times {{10}^{-3}}/K\]
Correct Answer: D
Solution :
Here, \[t=425{{\,}^{o}}C,{{R}_{0}}=4\Omega \] By ohms law \[V=I{{R}_{t}}\] \[\therefore \] \[3.5=0.28{{R}_{t}}\] \[\frac{350}{28}={{R}_{t}}\] \[{{R}_{t}}=12.5\Omega \] Resistance at temperature \[t{{\,}^{o}}C\]is, \[{{R}_{t}}={{R}_{0}}(1+\alpha t)\]where\[\alpha \]is temperature coefficient of resistance. \[\therefore \] \[12.5=4(1+\alpha \times 425)\] or \[\frac{12.5}{4}-1=\alpha \times 425\] or \[\frac{8.5}{4}=\alpha \times 425\] \[\alpha =\frac{8.5}{4\times 425}\] \[=0.5\times {{10}^{-2}}\] \[=5\times {{10}^{-3}}/K\]You need to login to perform this action.
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