A beam with wavelength 
falls on a stack of partially reflecting planes with separation d. The angle q that the beam should make with the planes so that the beams reflected from successive planes may interfere constructively is (where n = 1, 2, ……)
|
(a) |
(b) |
(c) |
(d) |
(c) 
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A nucleus 
emits one α and one β particles. The resulting nucleus is
|
(a) |
(b) |
(c) |
(d) |
Two infinitely long parallel conducting plates having surface charge densities +σ and -σ respectively, are separated by a small distance. The medium between the plates is vacuum. If 
is the dielectric permittivity of vacuum, then the electric field in the region between the plates is
|
(a) 0 volts/meter |
(b) |
(c) |
(d) |
A thermo couple develops 200μV between 0℃ and 100℃. If it develops 64μV and 76μV respectively between (0℃ - 32℃) and (32℃ - 70℃) then what will be the thermo emf it develops between 70℃ and 100℃
|
(a) 65 μV |
(b) 60 μV |
(c) 55 μV |
(d) 50 μV |
Two small bar magnets are placed in a line with like poles facing each other at a certain distance d apart. If the length of each magnet is negligible as compared to d, the force between them will be inversely proportional to
|
(a) d |
(b) |
(c) |
(d) |
