Question

Charge passes through a conductor of cross section at area $A=0.3m^2$ is given by $q=3t^2+5t+2$ in coloumb, where t is in second. What is the value of drift velocity at t = 2 sec (given n = $2\times {10}^{25}/m^2$)?

• A. $0.77\times {10}^{-5}m/s$
• B. $1.77\times {10}^{-5}m/s$
• C. $2.08\times {10}^{-5}m/s$
• D. $0.57\times {10}^{-5}m/s$

Answer 1

The correct option is B $1.77\times {10}^{-5}m/s$

$A=0.2m^{2}n=2\times {10}^{25}{m}^{-2}q=3t^2+5t+2\frac{dq}{dr}=i=6t+5(t=2s)=6\times 2+5=17Ai=neA{v}_d{v}_d=\frac{17}{2\times {10}^{25}\times 1.6\times {10}^{-19}\times 0.3}{v}_d=1.77\times {10}^{-5}m/s$