List of top Physics Questions asked in MHT CET

A thin lens of glass of refractive index 1.5 has focal length 24 cm in air. It is now immersed in a liquid of refractive index \( \frac{9}{8} \). Its new focal length is:

In a semiconductor diode, the barrier potential offers opposition to only:

A vector \( \mathbf{P} \) has components along X and Y axis having magnitude 2 units and 4 units respectively. A vector along negative X-axis, \( \mathbf{Q} \) has magnitude 6 units. Then vector \( (\mathbf{P} - \mathbf{Q}) \) is:

A block of mass \( m \) collides with another stationary block of mass \( 2m \). The lighter block comes to rest after collision. If the velocity of the first block is \( u \), then the value of the coefficient of restitution is:

A large number of liquid drops each of radius \( r \) coalesce to form a big drop of radius \( R \). The energy released in the process is converted into kinetic energy of the big drop. The speed of the big drop is: (T = surface tension of liquid, \( \rho = \) density of liquid)

If number of turns in moving coil galvanometer becomes half, then the deflection for the same current will become:

A particle starting from mean position oscillates simple harmonically with period 4 s. After what time will its kinetic energy be 75% of the total energy? (cos \( 30^\circ = \frac{\sqrt{3}}{2} \))

A circular disc \( X \) of radius \( R \) made from iron plate of thickness \( t \) has moment of inertia \( I_x \) about an axis passing through the centre of the disc and perpendicular to its plane. Another disc \( Y \) of radius \( 3R \) made from an iron plate of thickness \( \frac{t}{3} \) has moment of inertia \( I_y \) about the axis same as that of disc X. The relation between \( I_x \) and \( I_y \) is:

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\(^2\))

A wooden block is placed on a rough horizontal surface. It is given a velocity \( u \) m/s and the coefficient of friction between the block and the surface is \( \mu \). The distance covered by the block before coming to rest is: (g = acceleration due to gravity)

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:

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:

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:

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:

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):

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

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:

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

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, \( c = 3 \times 10^8 \, \text{m/s} \)]