If a coil of `40` turns and area `4.0 cm^(2)` is suddenly remove from a magnetic field, it is observed that a charge of `2.0xx10^(-4)C` flows into the coil. If the resistance of the coil is `80Omega`, the magnetic flux density in `Wb//m^(2)` is

Options

A. 0.5
B. 1
C. 1.5
D. 2

Answer

B

Explanation

Charge, `DeltaQ=(Deltaphi)/(R)=(nxxBA)/(R)`
`rArr` Magnetic flux density,
`B=(DeltaQ.R)/(nA)=(2xx10^(-4)xx80)/(40xx4xx10^(-4))=1"Wb/m"^(2)`