A23-turn circular coil of radius 3.40 cm and resistance 1.00 ω is placed in a magnetic field directed perpendicular to the plane of the coil. the magnitude of the magnetic field varies in time according to the expression b = 0.010 0t + 0.040 0t2, where b is in teslas and t is in seconds.

calculate the induced emf in the coil at t = 5.40 s.

Emf will be                

Explanation:

We have given number of turns N = 23

Radius of the coil r = 3.40 cm = 0.034 m

So area of the coil

Magnetic field is given as

We have to find the emf at t = 5.4 sec

We know that emf is given by

So emf at t = 5.4 sec

the higher the current the higher the mag field around it the higher the influence on the compass

compass can be used day and night, cloudy or sunny