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

Energy needed in breaking a drop of radius R into n drops each of radius r is given by ____________.

Assertion: If work done in increasing the size of a soap film from 10 cm x 4 cm to 10 cm x 8 cm is 2 x 10^-4 J, then the surface tension is 5 x 10^-4 N m^-1.

Reason: Work done = Surface tension x increase in area.

If two identical mercury drops are combined to form a single drop, then its temperature will ____________.

Four solid spheres each of mass M and radius R are placed with their centres on the four comers of a rectangle. If b is a breadth of rectangle and its length is twice of its breadth, then find moment of inertia of the system about an axis along one of the breadth of the rectangle.

In Rutherford experiment, for head-on collision of a-particles with a gold nucleus, the impact parameter is ______.

Soap solution bubble having radius `1/sqrtπ` cm is expanded to a bubble of radius `4/sqrtπ`. If the surface tension of soap solution is 30 dyne/cm, then the work done is ______.

Three identical rods each of mass 'M' and length 'L' are joined to form a symbol 'H'. The moment of inertia of the system about one of the sides of 'H' is ______.

A block of mass 'm' moving on a frictionless surface at speed 'v' collides elastically with a block of same mass, initially at rest. Now the first block moves at an angle 'θ' with its initial direction and has speed 'v₁'. The speed of the second block after collision is ______.

Which one of the following statements is correct?

A particle is performing U.C.M. along the circumference of a circle of diameter 50 cm with frequency 2 Hz. The acceleration of the particle in m/s² is ______.

A ball of mass 0.1 kg makes an elastic head-on collision with a ball of unknown mass, initially at rest. If the 0 .1 kg ball rebounds at one-third of its original speed, the mass of the other ball is ______.

A metal wire of density 'p' floats on water surface horizontally. If it is NOT to sink in water then maximum radius of wire is proportional to ______.

(T = surface tension of water, g = gravitational acceleration) 

Two spherical soap bubbles of radii r₁ and r₂ in vacuum coalesce under isothermal conditions. The resulting bubble has a radius R such that ____________.

A liquid drop having surface energy 'E' is spread into 216 droplets of same size. The final surface energy of the droplets is ____________.

The surface energy of a liquid drop is u. If it is sprayed into 1000 equal droplets, then its surface energy becomes ______.

Two current-carrying coils have radii r and 4r and have same magnetic induction at their centres. The ratio of voltage applied across them is ______.

A flywheel of mass 20 kg and radius 5 cm is revolving at a speed of 300 rpm. Its kinetic energy is ______.

If I₁ is the moment of inertia of a thin rod about an axis perpendicular to its length and passing through its centre of mass and I₂ is the moment of inertia of the ring formed by bending the rod about an axis perpendicular to the plane, the ratio of I₁ and I₂ is ____________.

A bomb of mass 9 kg explodes into two pieces of mass 3 kg and 6 kg. The velocity of mass 3 kg is 16 m/s, The kinetic energy of mass 6 kg is ____________.

Heat energy is incident on the surface at the rate of 2000 J/min. If coefficient of absorption is 0.8 and coefficient of reflection is 0.1 then heat energy transmitted by the surface in 10 minutes is ____________.