NTA Abhyas JEE Main2020PhysicsElectromagnetic InductionPractice
A solenoid has 2000 turns wound over a length of 0 .30 m . The area of its cross section is 1.2 × 10 - 3 m 2 . Around its central section, a coil of 300 turns is wound. If an initial current of 2 A in the solenoid is reversed in 0 .25 s , then the emf induced in the coil is equal to
Options
- A8.6 × 10 - 2 V
- B4.8 × 10 - 2 V
- C1.2 × 10 - 2 V
- D6.0 × 10 - 2 V
Correct answer
B. 4.8 × 10 - 2 V
Step-by-step solution
E m f = M d i d t =   μ 0 N 1 N 2 A l d i d t = 4 π × 10 - 7 × 2000 × 300 × 1.2 × 10 - 3 4 0.3 × 0.25 = 4.8 × 10 - 2 V