NEET-XII-Physics
P1 year:2019
- #41A 800 turn coil of effective area
0.05 ``m^2 ``is kept perpendicular to a magnetic
field 5 × ``10^{-5}`` T. When the plane of the coil
is rotated by 90° around any of its coplanar axis in
0.1 s, the emf induced in the coil will be:
(1) 2 V
(2) 0.2 V
(3) 2 × ``10^{-3} V
(4) 0.02 VdigAnsr: 4Ans : ( 4 )
Sol. Magnetic field B = 5 × 10-5 T
Number of turns in coil N = 800
Area of coil A = 0.05 m2
Time taken to rotate ▵t = 0.1 s
Initial angle
1
= 0°
Final angle
2
= 90°
Change in magnetic flux ▵
= NBAcos90° - BAcos0°
= - NBA
= - 800 × 5 × 10-5 × 0.05
= - 2 × 10-3 weber
▵=
▵
e -
t
= =
3( )2 10 Wb
0.02 V
0.1 s