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

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 ____________.

The equation of a wave of amplitude 0.02 m and period 0.04 s travelling along a stretched string with a velocity of 25 m/s will be ____________.

In photoelectric effect, graph of saturation current versus frequency of light is plotted. The nature of the graph will be ____________.

Which one of the following proportionality represents the relation between orbital magnetic moment M₀ and orbital angular momentum L₀ of an electron?

Metal rings 'P' and 'Q' are lying in the same plane where current 'I' is increasing steadily. The induced current in metal rings is shown correctly in figure.

Thomson's atomic model could not explain ____________ successfully.

Light of frequency 2 times the threshold frequency is incident on a photo sensitive material. If the frequency is made `1/3`rd and intensity is doubled then the photocurrent will ______.

When wavelength of incident radiation on the metal surface is reduced from 'λ₁' to 'λ₂', the kinetic energy of emitted photoelectrons is tripled. The work function of the metal is ______.
(h = Planck's constant, c =velocity of light)

When light of wavelength 'λ' is incident on a photosensitive surface, the stopping potential is 'V'. When light of wavelength '3λ' is incident on the same surface, the stopping potential is `"V"/6`. Threshold wavelength for the surface is _______.

The photo electric effect to take place for a metal, the minimum frequency required is 5.792 × 10¹⁴ Hz. A light of wavelength 6000 Å is incident on that metal surface. What is the corresponding frequency of light and will there be photoelectric emissions? [velocity of light = 3 × 10⁸ m/s]

Photoelectrons are emitted from a photosensitive surface for the light of wavelengths λ₁ = 360 nm and λ₂ = 600 nm. What is the ratio of work functions for lights of wavelength 'λ₁' to 'λ₂'?

When a surface 1 cm thick is illuminated by light of wavelength 'λ', the stopping potential is 'V₀'. When the same surface is illuminated by light of wavelength '3λ', the stopping potential is `"V"_0/6`. The threshold wavelength for the metallic surface is ______.

Light of different frequencies, whose photons have energies 3 eV and 18 eV respectively, successively illuminate a metal of work function 2 eV. The ratio of the maximum speeds of the emitted electrons will be ______.

The work function of a substance is 4.0 eV. The longest wavelength of light that can cause photo-emission from this substance is approximately (h = 6.63 × 10^-34 Js)[1eV = 1.6 × 10^-19 J]

The photon of frequency vis incident on a metal surface whose threshold frequency is v₀. The kinetic energy of the emitted photoelectrons will be ____________.

The r.m.s. value of induced voltage in a coil of 25 turns each of area 30 sq. cm. rotating at 2000 r.p.m. about an axis at right angles to magnetic field is (B = 5 x 10^-4 Wb/m²) ____________.