Explanation:
The locus of all particles in a medium, vibrating in the same phase is called wave front.
The direction of propagation of light (ray of light) is perpendicular to the wave front.
A wave front is an imaginary surface where all particles lying on this vibrate in the same phase.
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The minimum wavelength of X-rays produced in a coolidge tube operated at potential difference of 40 kV is
|
(a) 0.31 Å |
(b) 3.1 Å |
(c) 31 Å |
(d) 311 Å |
A potentiometer consists of a wire of length 4 m and resistance 10 W. It is connected to cell of emf 2 V. The potential difference per unit length of the wire will be
|
(a) 0.5 V/m |
(b) 10 V/m |
(c) 2 V/m |
(d) 5 V/m |
A magnetic needle suspended horizontally by an unspun silk fibre, oscillates in the horizontal plane because of the restoring force originating mainly from
| (a) The torsion of the silk fibre |
| (b) The force of gravity |
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(c) The horizontal component of earth's magnetic field |
| (d) All the above factors |
A tall man of height 6 feet, want to see his full image. Then required minimum length of the mirror will be-
An electron changes its position from orbit n = 4 to the orbit n = 2 of an atom. The wavelength of the emitted radiation’s is (R = Rydberg’s constant)
(a) 
|
(b) 
|
(c) 
|
(d) 
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