The speed of light in air is 3 × \(10^8\) m/s. If the refractive index of glass is 1.5, find the time taken by light to travel a distance 50 cm in glass.
(a) 2.5 × \(10^{-9}\) sec.
(b) 0.5 × \(10^{-9}\) sec.
(c) 0.16 × \(10^{-9}\) sec.
(d) 3 × \(10^{-9}\) sec.
(a) 2.5 × \(10^{-9}\) sec.
(b) 0.5 × \(10^{-9}\) sec.
(c) 0.16 × \(10^{-9}\) sec.
(d) 3 × \(10^{-9}\) sec.
(a) 2.5 × \(10^{-9}\) sec.
The angular resolution of a 10 cm diameter telescope at a wavelength of 5000 A is of the order of
(a) \(10^6\) rad
(b) \(10^{-2}\) rad
(c) \(10^{-4}\) rad
(d) \(10^{-6}\) rad
The refractive index of glass is 1.5 for light waves of wavelength 6000 Å in vacuum. Its wavelength in glass is
(a) 2000 Å
(b) 4000 Å
(c) 1000 Å
(d) 3000 Å
Ratio of intensities of two waves are given by 4 :1. Then the ratio of the amplitudes of the two waves.
(a) 2 : 1
(b) 1 : 2
(c) 4 : 1
(d) 1 : 4
The ratio of intensities at minima to the maxima in young’s double slit experiment is 9 : 25. Find the ratio of the widths of two slits.
(A) 16: 1
(B) 1: 16
(C) 4 : 1
(D) 1 : 4
The locus of all particles in a medium, vibrating in the same phase is called
(a) wavelet.
(b) fringe.
(c) wave front.
(d) None of these.
When ordinary light is made incident on a quarter wave plate, the emergent light is
(a) linearly polarised.
(b) circularly polarised.
(c) unpolarised.
(d) elliptically polarised.
In the phenomena of Diffraction of light when the violet light is used in the experiment is used instead of red light then.
(a) Fringe width increases.
(b) No change in fridge width.
(c) Fringe width decreases.
(d) Colour pattern is formed.
The refractive index of glass is 1.5 for light waves of wavelength 6000 Å in vacuum. Its wavelength in glass is
(a) 2000 Å
(b) 4000 Å
(c) 1000 Å
(d) 3000 Å
What type of wave front will emerge from any distant source of light?
i. Spherical wave front
ii. Cylindrical wave front
iii. Plane wave front
iv. None of these
What is the SI unit of electric potential?
(a) J/C
(b) J-C
(c) v-m
(d) J/c-m
The amount of work required to increase the distance between -6µC and 4µC from 6 cm to 18 cm will be :
(a) 1.8 J
(b) 2.4 J
(c) 1.8 µJ
(d) 2.4 µJ
Which of the following phenomenon is not explained by Huygen’s wave theory?
(a) Diffraction
(b) Polarisation
(c) Photoelectric effect
(d) Interference
15 joule of work has to be done against an existing electric field to take charge of 0.01C from A to B . Then potential difference ( \(V_B\) –\(V_A\))is
1. 1500 volts
2. -1500 V
3 .0.15 Volt
4 .15 Volt
An air capacitor is charged with an amount of charge q and dipped into an oil tank. If the oil is pumped out, the electric field between the plates of capacitor will
(a) increase
(b) decrease
(c) remain the same
(d) becomes zero