MAH-MHT CET (PCM/PCB) entrance exam Question Bank Solutions for Physics

An important spectral emission line has a wavelength of 21 cm. The corresponding photon energy is (h = 6.62 x 10^-34 Js, c = 3 x 10⁸ m/s) ____________.

An electron is accelerated through a potential difference of 10,000 V. Its de Broglie wavelength is, ______.

(nearly) (m_e= 9 x 10^-31 kg)

The electron in the hydrogen atom is moving with a speed of 1.5 x 10⁶ m/s in an orbit of radius 2 Å. Magnetic moment of the revolving electron is ____________.

A particle is executing simple harmonic motion with frequency f. The frequency at which its kinetic energy changes into potential energy is ______.

Light of wavelength `lambda` strikes a photo-sensitive surface and electrons are ejected with kinetic energy E. If the kinetic energy is to be increased to 2E, the wavelength must be changed to `lambda'` where ____________.

Instrument which measures alternating current is based on ____________.

A 60 `Omega` electric heater is connected to a 200 V, 50 Hz mains supply. The peak value of electric current flowing in the circuit is approximately ______.

Eddy currents are produced in a material when it is ____________.

The equation of a wave is y = 60 cos (1800t - 6x), where y is in microns, t in seconds, and x in metres. The ratio of maximum particle velocity to the wave velocity of wave propagation is ______.

Threshold wavelength for lithium metal is 6250 Å. For photoemission, the wavelength of the incident light must be ______.

The threshold frequency for a certain photosensitive metal is v₀. When it is illuminated by light of frequency v = 2v₀, the maximum velocity of photoelectrons is v₀. What will be the maximum velocity of the photoelectrons when the same metal is illuminated by light of frequency 

v = 5v₀?

In photoelectric effect, for a light of different intensities but of same frequency, the stopping potential for a given metal is ____________.

A coil having effective area A, is held with its plane normal to a magnetic field of induction B. The magnetic induction is quickly reduced to 25% of its initial value in 4 s. Then e.m.f. induced across the coil will be ____________.

A conducting circular loop is placed in a uniform magnetic field 0.02 T with its plane perpendicular to the magnetic field. The radius of the loop starts shrinking at 2 mm/s. The induced e.m.f. in the loop when the radius is 2 cm will be ____________.

What is the r.m.s. value of an alternating current which when passed through a resistor produces heat which is four times of that produced by a direct current of 3 ampere in the same resistor?

A metal surface is illuminated by photons of energy 5 eV and 2.5 eV respectively. The ratio of their wavelengths is ____________.

In a hydrogen atom, an electron of charge e revolves in a orbit of radius r with speed v. Then, the magnetic moment associated with electron is ______.

Equation of a plane progressive wave is given by `"y" = 0.6  "sin"2pi ("t" - "x"/2)`. On reflection from 48. denser medium its amplitude become `2/3` of the amplitude of the incident wave. The equation of the reflected wave is ____________.

When certain metal surface is illuminated with a light of wavelength A., the stopping potential is V, When the same surface is illuminated by light of wavelength 2λ, the stopping potential is `("V"/3)`. The threshold wavelength for the surface is ______.

The rate of change of magnetic flux density through a circular coil of area 10^-2 m² and number of turns 200 is 10³ Wb/m² s. The value of induced e.m.f. will be ____________.