HSC Science (Electronics) 12th Standard Board Exam - Maharashtra State Board Important Questions

In Doppler effect of light, the term “red shift” is used for ______.

(A) frequency increase

(B) frequency decrease

(C) wavelength decrease

(D) frequency and wavelength increase

If a watch-glass containing a small quantity of water is placed on two dissimilar magnetic poles, then water ______.

Doppler effect is not applicable when _______.
(A) source and observer are at rest.
(B) there is a relative motion between source and observer.
(C) both are moving in opposite directions.
(D) both are moving in same direction with different velocities

Explain the construction of plane wavefront using Huygens’ principle.

The refractive indices of glass and water w.r.t. air are 3/2 and 4/3 respectively. Determine the refractive index of glass w.r.t. water.

The working of RADAR is based on ...............

a) resonance

b) speed of a star

c) Doppler effect

d) speed of rotation of sun

Determine the change in wavelenght of light during its passage from air to glass, if the refracrtive index of glass with respect to air is 1.5 and the frequency of light is 5 x 10¹⁴ Hz. Find the wave number of light in glass (velocity of light in air c = 3 X 10⁸ m/s)

Apparent frequency of the sound heard by a listener is less than the actual frequency of sound emitted by source. In this case _______.

(A) listener moves towards source

(B) source moves towards listener

(C) listener moves away from the source.

(D) source and listener move towards each other.

The refractive indices of water for red and violet colours are 1.325 and 1.334 respectively.
Find the difference between the velocities of rays for these two colours in water. (c = 3 × 10⁸ m/s)

The minimum angular separation between two stars is 4 × 10⁻⁶ rad, if telescope is used to observe them with an objective of aperture 16 cm. Find the wavelength of light used.

A ray of light passes from a vacuum to a medium of refractive index (μ). The angle of
incidence is found to be twice the angle of refraction. The angle of incidence is _______.

A) `cos^(-1)(mu/2)`

B) cos⁻¹(μ)

C)  `2 cos^(-1) (mu/2)`

D) `2 sin^(-1) (mu/2)`

State any four applications of Doppler effect

State two uses of Polaroid.

The glass plate of refractive index 1.732 is to be used as a polarizer, its polarising angle is _______.

The refractive indices of water and diamond are `4/3` and 2.42 respectively. Find the speed of light in water and diamond. (c = 3x10⁸ m/s)

A cyclotron is used to accelerate protons to a kinetic energy of 5 MeV. If the strength of magnetic field in the cyclotron is 2T, find the radius and the frequency needed for the applied alternating voltage of the cyclotron. (Given : Velocity of proton= `3xx10^7 m//s`)

Explain refraction of light on the basis of wave theory. Hence prove the laws of refraction

State Brewster’s law and show that when light is incident at polarizing angle the reflected and refracted rays are mutually perpendicular to each other.

Calculate the value of the magnetic field at a distance of 2 cm from a very long straight wire carrying a current of 5 A (Given: μ₀ = 4π × 10^-7 Wb/Am).

Choose the correct option.

A conducting thick copper rod of length 1 m carries a current of 15A and is located on the Earth's equator. There the magnetic flux lines of Earth's magnetic field are horizontal, with the field of 1.3 x 10^-4T, south to north. The magnitude and direction of the force on the rod, when it is oriented so that current flows from west to east are ______.