Current Electricity Charging Discharging Of Capacitors Question 667
Question: When 5V potential difference is applied across a wire of length 0.1 m, the drift speed of electrons is $ 2.5\times {{10}^{-4}}m{{s}^{-1}} $ If the electron density in the wire is $ 8\times 10^{28}{{m}^{-3}}s $ , the resistivity of the material is close to
Options:
A) $ 1.6\times {{10}^{-8}}\Omega ,m $
B) $ 1.6\times {{10}^{-7}}\Omega ,m $
C) $ 1.6\times {{10}^{-6}}\Omega ,m $
D) $ 1.6\times {{10}^{-5}}\Omega ,m $
Show Answer
Answer:
Correct Answer: D
Solution:
[d] $ V=IR=I\rho\frac{l}{A} $
$ \Rightarrow \rho =\frac{VA}{Il}=\frac{VA}{In,e,Av _{d}}=\frac{V}{l\times n\times e\times v _{d}} $
$ \Rightarrow \rho =\frac{5}{0.1\times 2.5\times {{10}^{-19}}\times 1.6\times {{10}^{-19}}\times 8\times 10^{28}} $
$ =1.6\times {{10}^{-5}}\Omega ,m $
BETA
