Some questions....help

Question

Magnetic flux produced by magnetic filed B that through perpendicularly a surface of width A is P.If the magnetic field is reduced into B/2,but the width surface enlarged to 2A,then flux produced is...

A.P/4
B.P/2
C.P
D.2P
E.4P

Answer 1

You mean a surface of area A?

 

P = BA

 

P' = B'A' = (B/2)(2A) = BA = P

 

The correct answer is (C)