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

An iron plate has a circular hole of a diameter 11 cm. Find the diameter of the hole when the plate is uniformly heated from 10° C to 90° C.`[alpha = 12 xx 10^-6//°"C"]`

According to Bohr's theory, the expression for the kinetic and potential energy of an electron revolving in an orbit is given respectively by ______.

The binding energy of an electron in n^th orbit of the hydrogen atom is given by `"E"_"n" = 13.6/"n"^2 "eV."` The energy required to knock an electron from the second orbit in eV will be ____________.

A metre scale made of a metal reads accurately at 25 °C. Suppose in an experiment an accuracy of 0.12 mm in 1 m is required, the range of temperature in which the experiment can be performed with this metre scale is ______.(coefficient of linear expansion of the metal is `20 xx 10^-6 / (°"C")`

A metal sphere 10.01 cm in diameter is placed on a brass ring of internal diameter 10 cm and at the same temperature of 12° C. The temperature up to which they should be heated together so that the metal sphere just passes through the ring is `[alpha_"metal"= 12 xx 10^-6//°"C" and alpha_"brass" =18 xx 10^-6//°"C"]` ____________.

For an electron, discrete energy levels are characterised by ____________.

If m is mass of electron, v its velocity, r the radius of stationary circular orbit around a nucleus with charge Ze, then from Bohr's second postulate, the kinetic energy `"K.E." = 1/2"mv"^2` of the electron in C.G.S. system is 2 equal to ____________.

The unit of intensity of polarization is ____________.

The average translational kinetic energy of a molecule in a gas becomes equal to 0.49 eV at a temperature about (Boltzmann constant = 1.38 x 10^-23 JK^-1) ____________.

Which of the following models was successful in explaining the observed hydrogen spectrum?

If the speed of an electron of hydrogen atom in the ground state is 2.2 x 10⁶ m/s, then its speed in the third excited state will be ______.

In hydrogen emission spectrum, for any series, the principal quantum number is n. Corresponding maximum wavelength λ is ______.
(R = Rydberg's constant)

The acceleration of electron in the first orbit of hydrogen atom is ______.

For the weight of body of mass 5 kg to be zero on equator of the earth, angular velocity of the earth must be (The radius of earth = 6400 km, acceleration due to gravity = 10 m/s²).

A metal rod is heated to t°C. A metal rod has length, area of cross-section, Young's modulus and coefficient of linear expansion as 'L', 'A', 'Y' and 'a' respectively. When the rod is heated, the work performed is ______.

A metal rod of Young's moduls 'Y' and coefficient of linear expansion 'a' has its temeprature raised by 'Δ θ'. The linear stress to prevent the expansion of rod is ______.
(L and l is original length of rod and expansion respectively)

The equation of a plane progressive wave is y = 0.09sin8 `pi` `["t" - "x"/20]`.When it is reflected at a rigid support, its amplitude becomes `2/3`rd of its 3 previous value. The equation of the reflected wave is ______.

The time of revolution of an electron around a nucleus of charge Ze in n^th Bohr orbit is directly proportional to ____________.

Average kinetic energy of H₂ molecule at 300K is 'E'. At the same temperature, average kinetic energy of O₂ molecule will be ______.

The force of gravitation between two bodies of mass 1 kg each separated by a distance of 1 m in vacuum is ____________.