HSC Science (Computer Science) 12th Standard Board Exam - Maharashtra State Board Question Bank Solutions

What is Magnetization?

What is Magnetization?

The threshold wavelength of silver is 3800Å. Calculate the maximum kinetic energy in eV of photoelectrons emitted, when ultraviolet light of wavelength 2600Å falls on it.

(Planck’s constant, h =6.63 x 1O^-34J.s.,

Velocity of light in air, c = 3 x 10⁸ m / s)

In a set, 21 turning forks are arranged in a series of decreasing frequencies. Each tuning fork produces 4 beats per second with the preceding fork. If the first fork is an octave of the last fork, find the frequencies of the first and tenth fork.

Which one of the following particles cannot be accelerated by a cyclotron?

(A) Electrons

(B) Protons

(C) Deuterons

(D) α- particles

Which one of the following particles cannot be accelerated by a cyclotron?

(A) Electrons

(B) Protons

(C) Deuterons

(D) α- particles

The momentum of a photon of de Broglie wavelength 5000Å is _______.

[Planck’s constant = 6.63 x10^-34 J.s.]

With the help of a neat circuit diagram, explain the working of a photodiode. 

The maximum velocity of a particle performing linear S.H.M. is 0.16 m/s. If its maximum acceleration is 0.64 m/s², calculate its period.

A thin wire of length L and uniform linear mass density r is bent into a circular coil. M. I. of the coil about tangential axis in its plane is ................................

1. `(3rhoL^2)/(8pi^2)`
2. `(8pi^2)/(3rhoL^2)`
3. `(3rhoL^3)/(8pi^2)`
4. `(8pi^2)/(3rhoL^3)`

The value of end correction for an open organ pipe of radius 'r' is .........................

A) 0.3 r

B) 0.6 r

C) 0.9 r

D) 1.2 r

A body starts rotating from rest. Due to a couple of 20 Nm it completes 60 revolutions in one minute. Find the moment of inertia of the body.

The magnetic moment of a magnet of dimensions 5 cm × 2.5 cm × 1.25 cm is 3 Am². Calculate the intensity of magnetization.

The magnetic moment of a magnet of dimensions 5 cm × 2.5 cm × 1.25 cm is 3 Am². Calculate the intensity of magnetization.

When radiations of wavelength λ₁ and λ₂ are incident on certain photosensitive, such that E₁ > E₂ . Then Planck's constant 'h' is ......................... .

(C = Velocity of light).

Colour of light emitted by LED depends upon__________________ .

1. its forward bias
2. its reverse bias
3. the band gap of the material of semiconductor
4. its size

Two parallel plates separated by distance d are kept at potential difference V volt. A charge q of mass m enters in parallel plates with some velocity. The acceleration of the charged particle will be_____________________________ .

1. q V/d m
2. d m/ q V
3. q m/d V
4. d V/q m

Explain the phenomenon of self induction

The photoelectric threshold wavelength of a metal is 230 nm. Determine the maximum kinetic energy in joule and in eV of the ejects electron for the metal surface when it is exposed to a radiation of wavelength 180 nm.

[Planck’s constant : h = 6.63 * 10^-34 Js, Velocity of light : C = 3 * 10⁸ m/s.]

A horizontal disc is freely rotating about a transverse axis passing through its centre at the rate of 100 revolutions per minute. A 20 gram blob of wax falls on the disc and sticks to the disc at a distance of 5 cm from its axis. Moment of intertia of the disc about its axis passing through its centre of mass is 2 x 10^-4 kg m². Calculate the new frequency of rotation of the disc.