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

The Brewster's angle for the glass-air interface is (54.74)°. If a ray of light passing from air to glass strickes at an angle of incidence 45°, then the angle of refraction is ______.
`[tan (54.74)° = sqrt2, sin 45 = 1/sqrt2]`

Bohr model is applied to a particle of mass 'm' and charge 'q' is moving in a plane under the influence of a transverse magnetic field 'B. The energy of the charged particle in the nth level will be (h = Planck's constant).

The wavelength of the first line in Balmer series in the hydrogen spectrum is 'λ'. What is the wavelength of the second line in the same series?

A clock pendulum having coefficient of linear expansion. α = 9 × 10^-7/°C^-1 has a period of 0.5 s at 20°C. If the clock is used in a climate, where the temperature is 30°C, how much time does the clock lose in each oscillation? (g = constant)

When photons of energy hv fall on a metal plate of work function 'W₀', photoelectrons of maximum kinetic energy 'K' are ejected. If the frequency of the radiation is doubled, the maximum kinetic energy of the ejected photoelectrons will be ______.

The average K.E. of hydrogen molecules at 27° C is E. The average K.E. at 627° C is ____________.

With the increase in principal quantum number, the energy difference between the two successive energy levels ____________.

A ring of mass m and radius r rotates about an axis passing through its centre and perpendicular to its plane with angular velocity `omega`. Its kinetic energy is ______.

The ratio of the velocity of the electron in the first orbit to that in the second orbit is ____________.

Which of the following statements about the Bohr model of the hydrogen atom is FALSE?

When the electron in hydrogen atom jumps from fourth Bohr orbit to second Bohr orbit, one gets the ______.

For a certain atom when the system moves from 2E level to E, a photon of wavelength `lambda` is emitted. The wavelength of photon produced during its transition from `(4"E")/3` level to E is ____________.

How many moles of electrons are required for reduction of 9 moles of Cr³⁺ to Cr?

If the ionisation potential of helium atom is 24.6 volt, the energy required to ionise it will be ____________.

Taking the Bohr radius as a₀= 53 pm, the radius of Li⁺⁺ ion in its ground state, on the basis of Bohr's model, will be about ______.

For which one of the following, Bohr model is not valid?

What is the de Broglie wavelength of an electron of energy 180 eV?

(Mass of electron = 9 x 10^-31 kg and Planck's constant = 6.6 x 10^-34 Js.)

In Bohr's model of hydrogen atom, the period of revolution of the electron in any orbit is proportional to ______.

In the n^th orbit, the energy of an electron `"E"_"n"= -13.6/"n"^2"eV"` for hydrogen atom. The energy required to take the electron from first orbit to second orbit will be ____________.

When hydrogen atom is in its first excited level, its radius is how many time its ground state radius?