The magnetic induction at a point P which is distant 4 cm from a long current carrying wire is 
. The field of induction at a distance 12 cm from the same current would be
|
(a) 3.33 |
(b) 1.11 |
(c) 3 |
(d) 9 |
(c) 3 
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Two identical thin rings each of radius R meters are coaxially placed at a distance R meters apart. If Q1 coulomb and Q2 coulomb are respectively the charges uniformly spread on the two rings, the work done in moving a charge qfrom the centre of one ring to that of other is
|
(a) Zero |
(b) |
(c) |
(d) |
In Young’s experiment, the ratio of maximum to minimum intensities of the fringe system is 4 : 1. The amplitudes of the coherent sources are in the ratio
|
(a) 4 : 1 |
(b) 3 : 1 |
(c) 2 : 1 |
(d) 1 : 1 |
When the angle of incidence on a material is 60°, the reflected light is completely polarized. The velocity of the refracted ray inside the material is (in ms–1)
|
(a) 3 |
(b) |
(c) |
(d) 0.5 |
A thermoelectric refrigerator works on
|
(a) Joule effect |
(b) Seeback effect |
(c) Peltier effect |
(d) Thermonic emission |
The half life of radioactive Radon is 3.8 days. The time at the end of which 1/20 th of the Radon sample will remain undecayed is (Given 
|
(a) 3.8 days |
(b) 16.5 days |
(c) 33 days |
(d) 76 days |
