Figure shown variation of magnetic field inside and outside two cylindrical wires P and Q carrying currents that are uniformly distributed across the cross section of wires. If current density for two wires are `J_(P)` and `J_(Q)` then

Options

A. `J_(P) = J_(Q)`
B. `J_(P) lt J_(Q)`
C. `J_(P) gt J_(Q)`
D. can't be decided

Answer

C

Explanation

At the surface of a current carrying wire
`B = (1)/(2)mu_(o) Jr`
`J prop (B)/(r )`
`:.` as slope of wire `P gt` slope of wire Q