Two infinite plane parallel sheets separated by a distance d have equal and opposite uniform charge densities σ. Electric field at a point between the sheets is
|
(a) Zero |
(b) |
|
(c) |
(d) Depends upon the location of the point |
(b) 
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In a photocell bichromatic light of wavelength 2475 Å and 6000 Å are incident on cathode whose work function is 4.8 eV. If a uniform magnetic field of 3 × 10–5 Tesla exists parallel to the plate, the radius of the path describe by the photoelectron will be (mass of electron = 9 × 10–31 kg)
|
(a) 1 cm |
(b) 5 cm |
(c) 10 cm |
(d) 25 cm |
The focal length of a convex mirror is 20 cm its radius of curvature will be
|
(a) 10 cm |
(b) 20 cm |
(c) 30 cm |
(d) 40 cm |
We use flint glass prism to disperse polychromatic light because light of different colours
|
(a) Travel with same speed |
|
(b) Travel with same speed but deviate differently due to the shape of the prism |
|
(c) Have different anisotropic properties while travelling through the prism |
|
(d) Travel with different speeds |
Light energy emitted by stars is due to
|
(a) Breaking of nuclei |
(b) Joining of nuclei |
|
(c) Burning of nuclei |
(d) Reflection of solar light |
If two light waves having same frequency have intensity ratio 4 : 1 and they interfere, the ratio of maximum to minimum intensity in the pattern will be
|
(a) 9 : 1 |
(b) 3 : 1 |
(c) 25 : 9 |
(d) 16 : 25 |
For total internal reflection to take place, the angle of incidence i and the refractive index μ of the medium must satisfy the inequality
|
(a) |
(b) |
(c) sin i < |
(d) sin i > |
