Question

A circular loop of radius 5 cm is placed with its

planeperpendicular to B. If the magnetic induction B changes from
0.1Wb/m2 to 0.5 Wb/m2 in 0.025 sec.,
calculatethe induced emf.

Answer 1

`emf=0.1257\ V`

Step-by-step explanation:

Given:

• radius of a circular loop,
  `r=5\ cm=0.05\ m`

• initial magnetic flux density,
  `B_i=0.1\ Wb.m^(-2)`

• final magnetic flux density,
  `B_f=0.5\ Wb.m^(-2)`

• time taken for the change in flux density,
  `t=0.025\ s`

Now using Faraday's Law of induced emf:

`emf=(\Delta (BA))/(t)` ............................(1)

Firstly we find the area of the loop:

`A=\pi.r^2`

`A=\pi* 0.05^2`

`A=0.0078\ m^2`

Now putting the respective values in eq. (1):

`emf=((0.5-0.1)* 0.0078)/(0.025)`

`emf=0.1257\ V`