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

Two rods of the same material, same length and same radius transfer a given amount of heat in t second when they are joined end-to-end. When the rods are joined one above the other, then they will transfer the same heat in the same conditions in time ______.

A spherical solid ball of volume V is made up of a material of density ρ₁. It is falling through the liquid of density ρ₂(ρ₂ < ρ₁). Assume that, the liquid applies a viscous force on the ball that is proportional to the square of the speed v_t, i.e., `["F"_"viscous" = "KV"_"t"^2]`, then the terminal speed of the ball is ______.

(g = acceleration due to gravity)

Two equal drops of water are falling through air with a steady velocity v. If the drops coalesce, the new velocity will be ______.

A sonometer wire under suitable tension having specific gravity p, vibrates with frequency n in air. If the load is completely immersed in water the frequency of vibration of wire will become

Water is flowing through a horizontal pipe of non-uniform cross-section. In the region of narrowest part inside the pipe, the water will have ______.

If mean radius of earth is R, its angular velocity is ro and the acceleration due to gravity at the surface of the earth is g, then the cube of the radius of the orbit of satellite will be ____________.

For regular shapes of the small body, which of the following statement is true?

A metal sphere is hanging from the ceiling of a vehicle. If the vehicle is moving along the horizontal road with uniform acceleration 'a' then the suspended thread of the sphere gets inclined to the vertical at an angle 'θ'. The value of acceleration 'a' is (g = acceleration due to gravity) ______.

An electron of stationary hydrogen atom jumps from 4^th energy level to ground level. The velocity that the photon acquired as a result of electron transition will be ______. (h = Planck's constant, R = Rydberg's constant, m = mass of photon)

The specific heat of hydrogen gas at constant pressure is Cp = 6.4 x 10³ cal/kg °C and at constant volume is Cv = 4.4 x 10³ cal/kg °C. If one kilogram of hydrogen gas is heated from 10 °C to 20 °C at constant pressure, the external work done on the gas to maintain it at constant pressure is ______.

The work of 146 kJ is performed in order to compress one-kilo mole of a gas adiabatically and in this process the temperature of the gas increases by 7 °C. The gas is ______.

(R = 8.3 J mol^-1 K^-1)

A Carnot engine operating between temperatures T₁ and T₂ has efficiency 0.2. When T₂ is reduced by 50 K, its efficiency increases to 0.4. Then T₁ and T₂ are respectively ______.

A Carnot engine whose low temperature reservoir is at 7°C has an efficiency of 50%. It is desired to increase the efficiency to 70%. By how many degrees should the temperature of the high temperature reservoir be increased?

One mole of an ideal diatomic gas undergoes a transition from A to B along a path AB as shown in the figure,

The change in internal energy of the gas during the transition is ____________.

A bucket full of hot water cools from 85 °C to 80 °C in time T₁, from 80 °C to 75 °C in time T₂ and from 75 °C to 70 °C in time T₃, then ______.

Rate of cooling of a body is 0.4 °C/min when excess temperature is 20 °C. The proportionality constant is ______.

A metal sphere cools from 66° C to 57° C in 10 minutes and to 44° C in the next 10 minutes. The ratio of fall of temperature of first 10 minutes to next ten minutes is ____________.

A liquid with a certain surface area takes 10 minutes to cool from 80° C to 70° C. The time taken by it to cool from 80° C to 60° C is [The surrounding temperature being 40° C] ____________.