List of top Questions asked in MHT CET- 2020

To what depth must a rubber ball be taken in deep sea so that its volume is decreased by 0.2%? The bulk modulus of rubber is \( 9.8 \times 10^8 \, \text{N/m}^2 \) and the density of sea water is \( 10^3 \, \text{kg/m}^3 \) (g = 9.8 m/s\(^2\))

Two wires carrying currents \( I \) and \( 2I \) (in opposite directions) are parallel to each other. Third wire carrying current \( I \) is placed midway between the two wires and anti-parallel to a wire carrying current \( I \). Force due to magnetic field on third wire will be:

Length of an organ pipe open at both ends is 34 cm. If velocity of sound is 340 m/s, then the frequency of 2nd overtone is:

Two identical wires of same length are vibrating in unison with a tuning fork, under same tension. The length of one wire is decreased by 1 cm and it produces 3 beats per second with the tuning fork. The length of the other wire is increased by 1 cm and it produces 2 beats per second with the tuning fork. If the original length of wire is 67 cm, the frequency of the tuning fork is:

The surface density of charge on the surface of a charged conductor in air is \( 0.885 \, \mu C/m^2 \). The outward force per unit area of charged conductor is:

An electron moving with initial velocity \( \mathbf{V} = V_0 \hat{i} \) is moving in a magnetic field \( \mathbf{B} = B \hat{k} \). Then its de-Broglie wavelength:

The r.m.s. velocity of hydrogen molecules at temperature \( T \) is seven times the r.m.s. velocity of nitrogen molecules at 300 K. This temperature \( T \) is (Molecular weights of hydrogen and nitrogen are 2 and 28 respectively):

Light of frequency 2 times the threshold frequency is incident on a photo-sensitive material. If the frequency is made \( \frac{1}{3} \)rd and intensity is doubled then the photocurrent will:

In the following circuit, the internal resistance of the cell is 5 \( \Omega \), the current drawn from the cell will be:

The third overtone of a closed pipe is in unison with the second overtone of an open pipe. Hence the ratio of the length of the closed pipe to that of the open pipe is:

Two rings of radii \( R \) and \( nR \) made from the same wire have the ratio of moments of inertia about an axis passing through their centre and perpendicular to the plane of the rings is 1 : 8. The value of \( n \) is:

The angle of polarisation for a medium is 60°. The critical angle for this will be \( \left( \tan 60^\circ = \sqrt{3} \right) \):

A particle of mass \( m \) is rotating in a horizontal circle of radius \( r \) with uniform velocity \( \mathbf{V} \). The change in its momentum at two diametrically opposite points will be:

In hydrogen atom, during the transition of electron from \( n \)th outer orbit to first Bohr orbit, a photon of wavelength \( \lambda \) is emitted. The value of \( n \) is: [\( R \) = Rydberg's constant]

In a series LCR circuit at resonance, the applied e.m.f. of the source and current in the circuit are:

The length of antenna required to transmit the signals of frequency \( 1.5 \times 10^8 \) Hz is [velocity of light in air, \( c = 3 \times 10^8 \, \text{m/s} \)]

When a ray of light is refracted from one medium to another, then the wavelength changes from 6000 Å to 4000 Å. The critical angle for the interface will be:

If \( I \) is the moment of inertia and \( L \) is angular momentum of a rotating body, then \( \frac{L^2}{2I} \) is its:

If the frequency of oscillation of a simple pendulum in simple harmonic motion is \( n \), then frequency of oscillation of simple pendulum when length is 4 times is:

Following graph shows the variation of load (\( W \)) versus elongation (\( l \)) for four wires of the same length and material represented by lines OP, OQ, OR, and OS. Which line represents the thickest wire?

The bob of a simple pendulum is released at time \( t = 0 \) from a position of small angular displacement. Its linear displacement is \( l \) (length of simple pendulum) and \( g \) (acceleration due to gravity), \( A \) = amplitude of S.H.M.

The sensitivity of a milliammeter of range 0 to 50 mA is \( \frac{x}{\text{div}} \, \text{mA} \). If it is converted into an ammeter of range 500 mA by using a suitable shunt then the sensitivity will be:

Let the physical quantity be \( x = \frac{a^3b^2}{c} \). If the percentage error in the measurement of \( a \), \( b \), and \( c \) is 2%, 3%, and 4% respectively, then the percentage error in the measurement of \( x \) is:

The phase difference between the voltage and the current in an a.c. circuit is \( \frac{\pi}{4} \). If the frequency is 50 Hz, then the phase difference is equivalent to a time of:

A particle of mass 4 gram moves along a circle of radius \( 10^2 / 2\pi \) cm with constant tangential acceleration. After beginning of the motion, by the end of second revolution, the kinetic energy of the particle becomes \( 18 \times 10^{-5} \) J. The magnitude of tangential acceleration is: