The average e.m.f. induced in a coil in which the current changes from 2 ampere to 4 ampere in 0.05 second is 8 volt. What is the self inductance of the coil ?
|
(a) 0.1 H |
(b) 0.2 H |
(c) 0.4 H |
(d) 0.8 H |
(b) 0.2 H
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The image distance of an object placed 10 cm in front of a thin lens of focal length + 5 cm is
|
(a) 6.5 cm |
(b) 8.0 cm |
(c) 9.5 cm |
(d) 10.0 cm |
The electric field in a region is radially outward with magnitude E = 
. The charge contained in a sphere of radius 
centered at the origin is
|
(a) |
(b) |
(c) |
(d) |
A permanent magnet
|
(a) Attracts all substances |
|
(b) Attracts only magnetic substances |
|
(c) Attracts magnetic substances and repels all non-magnetic substances |
|
(d) Attracts non-magnetic substances and repels magnetic substances |
Wavelength of light of frequency 100Hz
|
(a) 2 |
(b) 3 |
(c) 4 |
(d) 5 |
A coil of area 80 square cm and 50 turns is rotating with 2000 revolutions per minute about an axis perpendicular to a magnetic field of 0.05 Tesla. The maximum value of the e.m.f. developed in it is
|
(a) 200π volt |
(b) |
(c) |
(d) |
