NEET2017PhysicsElectromagnetic InductionActual
A circular coil of radius 10 ~cm , 500 turns and resistance 2 is placed with its plane perpendicular to the horizontal component of the earth's magnetic field. It is rotated about its vertical diameter through 180^ in 0.25 ~s . The current induced in the coil is (Horizontal component of the earth's magnetic field at that place is 3.0 10⁻⁵ ~T )
Options
- A1.9 10⁻³ ~A
- B2.9 10⁻³ ~A
- C3.9 10⁻³ ~A
- D4.9 10⁻³ ~A
Correct answer
A. 1.9 10⁻³ ~A
Step-by-step solution
Initial magnetic flux through the coil, aligned _i & =B_H A =3.0 10⁻⁵ ( 10⁻² ) 0^ & =3 10⁻⁷ ~Wb aligned Final magnetic flux after the rotation aligned _f & =3.0 10⁻⁵ ( 10⁻² ) 180^ & =-3 10⁻⁷ ~Wb aligned Induced emf, =-N d d t =- N ( _f- _i ) t aligned & =- 500 (-3 10⁻²-3 10⁻⁷ ) 0.25 & = 500 (6 10⁻⁷ ) 0.25 =3.8 10⁻³ ~V & I= R = 3.8 10⁻³ ~V 2 =1.9 10⁻³ ~A aligned