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

When two objects are said to be in thermal equilibrium?

Four resistances 4 Ω, 8Ω, XΩ and 12Ω are connected in a series to form Wheatstone’s network. If the network is balanced, the value of X is ______.

To convert a moving coil galvanometer into an ammeter we need to connect a ______.

Draw a neat labelled diagram for the construction of 'cyclotron'

Determine the change in wavelength of light during its passage from air to glass. If the refractive index of glass with respect to air is 1.5 and the frequency of light is 3.5 x 10¹⁴ Hz, find the wave number of light in glass.

[Velocity of light in air c = 3 x 10⁸ m/s]

Wavelengths of two notes in the air are`[70/153]^m` and `[70/157]^m`. Each of  these notes produces 8 beats per second with a tuning fork of fixed frequency. Find the velocity of sound in the air and frequency of the tuning fork.

In a cyclotron, magnetic field of 3·5Wb/m2 is used to accelerate protons. What should be the time interval in which the electric field between the Dees be reversed?
(Mass of proton = 1· 67 x 10^-27Kg, Charge on proton =1·6x10^-19c).

On the basis of Huygens' wave theory of light prove that velocity of light in a rarer medium is greater than velocity of light in a denser medium.

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

a) resonance

b) speed of a star

c) Doppler effect

d) speed of rotation of sun

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.

State any four applications of Doppler effect

Explain Ampere’s circuital law.

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.