IIT JAM Physics Mock Test - 8 - Physics MCQ

A clock keeps correct time, with what speed should it be moved to an observer so that it may appear to loose 5 minutes in 24 hours?

The rate of radiation of a black body at 0⁰C is E Watt. Then the rate of radiation of this black body at 273⁰C will be :

A harmonic oscillator has the wave function   is the eigenfunction belonging to the n^th energy eigenvalue  The expectation value <E> of energy for the state ψ(x,t) is

Consider a quantum mechanical system with three linear operators  which are related by  Where  is the unit operator. If  the  must be 

Electric field component of an electro magnetic radiation varies with time as  where a is a constant and the values of the ω and  respectively. This radiation falls on a metal of work function 2 eV. The maximum kinetic Energy of photoelectrons is.

The electrons x and y are moving with velocities 0.1 C and 0.8C respectively. The ratio of energies ΔE_X / ΔE_y required to increase the speed of each by 0.1 C is given approximately by

A particle A of mass m_A decays into two particles, one of which is B with mass m_B and the other massless. The magnitude of the momentum of particle B using relativistic kinematics in the first-frame of the particle A is

A driver is being fined for overlooking a red signal. The driver claimed that instead of red colour (v₀ = 4.8 * 10¹⁴ Hz) he saw green (v = 5.6 * 10¹⁴ Hz) because of Dopper effect. The judge fined the driver for speed at the rate of Rs. 1/- for each km/h he exceeded the speed limit of 80 km/h. What is the fine?

In a Devisson - Germer experiment a collimated beam of electrons of energy 54eV at a normal incidence on a given crystal, shows a peak appears at the same value of reflection angle, then the energy of the neutrons must be

The photo electric threshold of certain metal is 2750 A°. Find the maximum kinetic energy of the electrons. 

The velocity of an electron in the ground state of a hydrogen atom is V_H. If V_p be the velocity of an electron in the ground state of positronium, then

A beam of atoms moving in a certain direction can be slowed down if they absorb photons from a laser beam moving in the opposite direction and subsequently spontaneously emit photons isotropically. For a beam of sodium atoms (mass number A = 23) with speed 600 m/sec. If a laser beam of wavelength 589 nm is used the number of such absorption and emission cycles needed to bring a sodium atom to rest would be approximately________

An α-particle and a proton are fired through the same magnetic field which is perpendicular to their velocity vectors. The α-particle and the proton move such that radius of curvature of their path is same. What is the ratio of their de-Broglie wavelengths?

In a collision between a photon and a free electron, which is correct, if all the photon energy were transferred to the electron.

Denote the computer of two matrices A and by [A, B] = AB - BA and anti commutator by {A,B} = AB + BA 
If {A.B} = 0 we can write [A,B,C]

The activity of a radioactive sample is decreased by 25% of the initial value after 30 days. The half - life (in days) of the sample is approximately

Five identical non-interacting particles, each of spin 1/2 and mass m, are moving in a one-dimensional infinite potential well given by
 
The energy of the lowest energy state is

The frequency of electron in Bohr orbit is given by f₁ revolutions/sec. The frequency of electron in the n-th orbit for n > 1 is

An electron is moving inside a uniformly charged sphere with total charge +ve. The uncertainty principle ΔP_xΔx ≥ n is used for finding the smallest radius r_min of the charged sphere such that the kinetic energy of the electron is equal to its potential energy on the surface of the sphere. The r_min is approximately in the range    .

The Compton effect experiment photons of energy h v around material of atomic number Z. The change in wavelength can be

1.5 mW of 400 nm light is directed at a photo electric cell. If 0.1 % of the incident photon produce e-s. all the photo e^- s reach the opposite plate, so the current in the photo cell is equal to______ .

In a hydrogen - like atom, an election is the ground state requires 476 ev to reach an excited level with quantum number 2n. If it makes a transition from this level to a lower level with quantum number n, it emits a photon of energy 40.8 eV. Find the atomic number Z of the element

The speed of an electron, whose de Broglie wavelength is equal to its Compton wavelength, is (C is the speed of light)

A neutron of mass mn = 10^-27 kg is moving inside a nucleus. Assume the nucleus to be a cubical box of size 10^-14 m with impenetrable walls. Take Js and 1 MeV ≈ 10^-13 J . An estimate of the energy in Mev of the neutron is

The longest wavelength in the Balmer series of hydrogen atom is given as 656 nm positronium can be considered as a system of an electron and a positron in which both these particles orbit each other. What will be the longest wavelength in the lyman series for positronium?

Positronium is a hydrogen like bound state of a position and electron. If the nth energy level of hydrogen atoms is given by  the nth energy  of the positronium will be equal to

A particle has rest mass m₀ and momentum m₀c, where c is the velocity of light. The total energy and the velocity of the particle are respectively.