The contribution in the total current flowing through a semiconductor due to electrons and holes are 
and 
respectively. If the drift velocity of electrons is 
times that of holes at this temperature, then the ratio of concentration of electrons and holes is
|
(a) 6 : 5 |
(b) 5 : 6 |
(c) 3 : 2 |
(d) 2 : 3 |
(a) 6 : 5
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A charged particle is moving in a uniform magnetic field in a circular path. Radius of circular path is R. When energy of particle is doubled, then new radius will be
|
(a) R |
(b) |
(c) 2 R |
(d) 3 R |
Same current i = 2A is flowing in a wire frame as shown in figure. The frame is a combination of two equilateral triangles ACD and CDE of side 1m. It is placed in uniform magnetic field B = 4T acting perpendicular to the plane of frame. The magnitude of magnetic force acting on the frame is
|
(a) 24 N |
(b) Zero |
(c) 16 N |
(d) 8 N |
The galaxies are moving away from each other. It is explained by
|
(a) White dwarf star |
(b) Red shift |
(c) Neutron star |
(d) None of these |
Two identical magnetic dipoles of magnetic moments 1.0 A-m2 each, placed at a separation of 2m with their axis perpendicular to each other. The resultant magnetic field at a point midway between the dipoles is
(a) 5 
|
(b) 
|
(c)
|
(d) None of these |
