HSC Science (General) 12th Standard Board Exam - Maharashtra State Board Question Bank Solutions for Physics

Compare the rates of emission of heat by a blackbody maintained at 727°C and at 227°C, if the black bodies are surrounded by an enclosure (black) at 27°C. What would be the ratio of their rates of loss of heat?

Earth’s mean temperature can be assumed to be 280 K. How will the curve of blackbody radiation look like for this temperature? Find out λ_max. In which part of the electromagnetic spectrum, does this value lie? (Take Wien's constant b = 2.897 × 10⁻³ m K)

Find the temperature of a blackbody if its spectrum has a peak at (a) λ_max = 700 nm (visible), (b) λ_max = 3 cm (microwave region) (c) λ_max = 3 m (short radio waves). (Take Wien’s constant b = 2.897 × 10^-3 m.K).

An ideal monoatomic gas is adiabatically compressed so that its final temperature is twice its initial temperature. What is the ratio of the final pressure to its initial pressure?

Answer in brief.

Using differential equations of linear S.H.M, obtain the expression for (a) velocity in S.H.M., (b) acceleration in S.H.M.

Find the change in length of a second’s pendulum, if the acceleration due to gravity at the place changes from 9.75 m/s² to 9.8 m/s².

Answer in brief.

For a stationary wave set up in a string having both ends fixed, what is the ratio of the fundamental frequency to the second harmonic?

Derive an expression for the equation of stationary wave on a stretched string.

Find the amplitude of the resultant wave produced due to interference of two waves given as y₁ = A₁ sinωt, y₂ = A₂ sin(ωt + φ)

A standing wave is produced in a tube open at both ends. The fundamental frequency is 300 Hz. What is the length of the tube? (speed of the sound = 340 m s^-1).

A piece of straight wire has mass 20 g and length 1 m. It is to be levitated using a current of 1 A flowing through it and a perpendicular magnetic field B in a horizontal direction. What must be the magnitude B of the magnetic field?

An aircraft of wing span of 50 m flies horizontally in the Earth's magnetic field of 6 x 10^-5 T at a speed of 400 m/s. Calculate the emf generated between the tips of the wings of the aircraft.

A metal disc of radius 30 cm spins at 20 revolution per second about its transverse symmetry axis in a uniform magnetic field of 0.20 T. The field is parallel to the axis of rotation. Calculate
(a) the area swept out per second by the radius of the disc
(b) the flux cut per second by a radius of the disc
(c) the induced emf between the axle and rim of the disc.

The primary and secondary coils of a transformer each have an inductance of 200 x 10^-6 H. The mutual inductance between the windings is 4 x 10^-6 H. What percentage of the flux from one coil reaches the other?

A circular coil of 100 turns with a cross-sectional area of 1 m² is kept with its plane perpendicular to the magnetic field of 1 T. The magnetic flux linkage is ______.

Explain what you understand by the de Broglie wavelength of an electron. Will an electron at rest have an associated de Broglie wavelength? Justify your answer.

The de Broglie wavelengths associated with an electron and a proton are the same. What will be the ratio of

1. their momenta
2. their kinetic energies?

Two particles have the same de Broglie wavelength and one is moving four times as fast as the other. If the slower particle is an α-particle, what are the possibilities for the other particle?

Find the ratio of the de Broglie wavelengths of an electron and a proton when both are moving with the (a) same speed, (b) the same kinetic energy, and (c) the same momentum. State which of the two will have a longer wavelength in each case.

What is the amount of \[\ce{_27^60Co}\] necessary to provide a radioactive source of strength 10.0 mCi, its half-life being 5.3 years?