Question

If the current in a wire of a cd player is 12.0 ma, how long would it take for 6.50 c of charge to pass a point in this wire? answer in units of s.

Answer 1

The current intensity is defined as the amount of charge Q that passes through a certain point of an electrical wire in a time interval of
`\Delta t`:

`I= (Q)/(\Delta t)`

In our problem, the current intensity is

`I=12.0 mA=0.012 A`
while the amount of charge that passes a certain point of the wire is

`Q=6.50 C`

If we re-arrange the previous equation:

`\Delta t= (Q)/(I)`
we can find the time needed for this amount of charge to pass through a point of the wire:

`\Delta t= (6.50 C)/(0.012 A) =541.7 s`