Two coherent sources separated by distance d are radiating in phase having wavelength l. A detector moves in a big circle around the two sources in the plane of the two sources. The angular position of n = 4 interference maxima is given as
|
(a) |
(b) |
(c) |
(d) |
(b) 
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Two spheres A and B of radius ‘a’ and ‘b’ respectively are at same electric potential. The ratio of the surface charge densities of A and B is
|
(a) |
(b) |
(c) |
(d) |
A coil having an area 
is placed in a magnetic field which changes from 
to 
in a interval of 2 second. The e.m.f. induced in the coil will be
|
(a) 4 V |
(b) 3 V |
(c) 1.5 V |
(d) 2 V |
When objects at different distances are seen by the eye, which of the following remain constant?
If a lens is cut into two pieces perpendicular to the principal axis and only one part is used, the intensity of the image
|
(a) Remains same |
(b) |
(c) 2 times |
(d) Infinite |
The ionisation potential of H-atom is 13.6 V. When it is excited from ground state by monochromatic radiations of 970.6 
the number of emission lines will be (according to Bohr’s theory)
|
(a) 10 |
(b) 8 |
(c) 6 |
(d) 4 |
The number of photo-electrons emitted per second from a metal surface increases when
|
(a) The energy of incident photons increases |
|
(b) The frequency of incident light increases |
|
(c) The wavelength of the incident light increases |
|
(d) The intensity of the incident light increases |
Dielectric constant of pure water is 81. Its permittivity will be
|
(a) |
(b) 8.86 |
|
(c) 1.02 |
(d) Cannot be calculated |
