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

A water film is formed between the two straight parallel wires, each of length 10 cm, kept at a separation of 0.5 cm. Now, the separation between them is increased by 1 mm without breaking the water film. The work done for this is ______.

(surface tension of water = 7.2 x 10^-2Nm^-1)

A long solenoid carrying current 'I₁' produces magnetic field 'B₁' along its axis. If the current is reduced to 25% and number of turns per cm are increased four times, then new magnetic field 'B₂' is ____________.

Figure shows triangular lamina which can rotate about different axis of rotation. Moment of inertia is maximum about the axis ______.

Two bodies of masses 3 kg and 2 kg collide bead-on. Their relative velocities before and after collision are 20 m/s and 5 m/s respectively. The loss of kinetic energy of the system is ______.

Moment of inertia of the rod about an axis passing through the centre and perpendicular to its length is 'I₁'. The same rod is bent into a ring and its moment of inertia about the diameter is 'I₂', then `"I"_2/"I"_1` is ______.

The moment of inertia of a ring about an axis passing through its centre and perpendicular to its plane is 'I'. It is rotating with angular velocity 'ω'. Another identical ring is gently placed on it so that their centres coincide. If both the ring are rotating about the same axis, then loss in kinetic energy is ______.

A metal coin of thickness 'd' and density 'ρ' is floating on water of surface tension 'T'. The radius of the coin is ______.

g = acceleration due to gravity

The sum of the absorptance, reflectance, and transmittance of a body is ______.

A body of mas 'm' moving with speed 3 m/s collides with a body of mass '2m' at rest. The coalesced mass will start to move with a speed of ______.

A smooth sphere of mass 'M' moving with velocity 'u' directly collides elastically with another sphere of mass 'm' at rest. After collision, their final velocities are V' and V respectively. The value of V is given by ______.

A uniform disc of mass 4 kg has radius of 0.4 m. Its moment of inertia about an axis passing through a point on its circumference and perpendicular to its plane is ______.

A disc rolls down a smooth inclined plane without slipping. An inclined plane makes an angle of 60° with the vertical. The linear acceleration of the disc along the inclined plane is ______.

(g = acceleration due to gravity, sin 30° =cos 60° `=1/2,` sin 60° = cos 30° `=sqrt3/2`)

A thin circular ring of mas 'M' and radius 'R' is rotating about a transverse axis passing through its centre with constant angular velocity 'ω'. Two objects each of mass 'm' are attached gently to the opposite ends of a diameter of the ring. What is the new angular velocity?

A winding wire is used to prepare a solenoid that can bear a maximum current of 10A. If the length of a solenoid is 80 cm and its cross-sectional radius is 3 cm, the required length of winding wire is ____________.

(magnetic field B = 0.2 T, µ₀ = 4 x 10^-7 SI units)

A charged particle carrying a charge 'q' and moving with velocity V, enters into a solenoid carrying a current T, along its axis. If 'B' is the magnetic induction along the axis of a solenoid, then the force 'F' acting on the charged particle will be ____________.

One thousand small water drops of equal radii combine to form a big drop. The ratio of final surface energy to the total initial surface energy is ______.

An athermanous metal plate has the coefficient of absorption 0.65. Its coefficient of reflection is ______.

A bag of sand of mass 9.8 kg is suspended by a rope. A bullet of 200 g travelling with speed 10 ms^-1 gets embedded in it, then loss of kinetic energy will be ______.

The dimension of mutual inductance is ______.

A water drop of diameter 2 cm is broken into 64 equal droplets. The surface tension of water is 0.075 N/m. In this process the gain in surface energy will be ______.