Question

A coil of area 0.4 m2 has 100 turns. A magnetic field of 0.04 Wb m-2 is acting normal to the coil surface. If this magnetic field is reduced to zero in 0.01 s, then the induced emf in the coil is

• A. 160 V
• B. 250 V
• C. 270 V
• D. 320 V

Answer 1

Answer: (A)

160 V

Answer 2

Here $\mathrm { A } = 0.4 \mathrm {~m} ^ { 2 } , \mathrm {~N} = 100 , \mathrm {~dB} = 0.04 \mathrm { Wbm } ^ { - 2 }$

As $\varepsilon = \frac { \mathrm { d } \phi } { \mathrm { dt } } = \mathrm { NA } \frac { \mathrm { dB } } { \mathrm { dt } } = 100 \times 0.4 \times \frac { 0.04 } { 0.01 } = 160 \mathrm {~V}$