current

I THINK IT IS A
B AND C R ELIMINATED
DOUBTFUL ABOUT D

a) charge crossing in a given time interval.. i dunno how its independent.

b) and c) everyone knows its dependent...

d) free e- density = free e- per unit volume... if A changes, length will also change to kp the density constant... so this is independent..

but how A?

thinkng//...................

It can be proved I=nAev where I-->Current through the conductor.
n--> No of electrons per unit volume.
A--> area of cross section of conductor
e-->Charge on an electron.
v--> Drift velocity of each electron
Therefore
(A) q=nAevt --> Dependent on area of cross section.
(B) v= I/(nAev) --> Again dependent on area of cross section.
(C) Current density (J) =I/A

i think it should be (d) ... But i am not sure . Please correct me if i am wrong.

think the charge entering the smaller end has to pass through the rest of part n thus tokeep i constant

n for ur expression both a n vd ll change to make i constant

I = nAev
=> q/t = nAev
=> q = nAevt

actually i din understand wat u waana say

which part did'nt u understand?