Charge passing through a conductor of cross- section area A= 0.3 `m^2` is given by q = `3t^2 + 5t` + 2 in coulomb , where t is in second . What is the value of drift velocity at t= 2s? `(Given, n = 2xx10^25/m^3)`

Options

A. `0.77xx10^-5 m/s`
B. `1.77xx10^-5m/s `
C. `2.08xx10^-5m/s `
D. `0.57xx10^-5m/s `

Answer

A

Explanation

Equivalent resistance of parallel combination is ,
`R_(eq)= ((6)(12))/(6+12) = 4Omega`
`6Omega` resistance is connected in series
`R_(eq) = 4+6=10Omega`
From ohm's low ,V= iR
therefore `i= (10)/(10) = 1A`
Current through `12Omega` resister is given as
`i_2=i((R_1)/(R_1)+(R_c)) = ixx((6))/((6+12))=(1)/(3)`