Question

If the peak emf produced by AC generator is 440 volt and coil of area 20 cm² is rotated at the speed 1000 radian/sec in 0.1 T magnetic field, find the number of turns in coil,


2200

1100

4400

8000​

Answer 1

Given,

EMF produced = 440 v

Area of coil = 10 cm² = 10*10⁻⁴ m²

Speed = 1000 radian/sec

Magnetic field = 0.1 T

To Find,

The number of turns of the coil.

Solution,

The formula for calculating the EMF is

EMF = N B A w, where n is the number of turns, B is the magnetic field, A is area and w is angular speed.

440 = N×0.1×20×10^-4×1000

N=2200

Hence, the number of turns in the coil is 2200.

Answer 2

The number of turns in coil can be found out using The formula for calculating the EMF , which is

emf = N B A ω

where ,

• n is the number of turns
• B is the magnetic field
• A is area

• ω is angular speed.

Given ⇒ emf = 440 V

                   A = 20 cm²= 10*10⁻⁴ m²

                   ω = 1000 radian/sec

                  B = 0.1 T

Therefore N = emf / BAω

                     = $\frac{440}{0.1 * 1000 * 10 *10^{4} }$

                   N = 2200