11.

A water film is made between two 10 cm long straight wires and at a distance of 0.5 cm. If distance between the wires is increased by 1 mm, then work done will be (T = 7.2 x 10^-2N/m)

• 7.22 × 10^-6 J

• 1.44 × 10^-5 J

• 2.88 × 10^-5 J

• 5.76 × 10^-5 J

The average kinetic energy of a hydrogen gas molecule at NTP will be (Boltzmann's  constant k = 138 x 10^-23 J/K)

• 0.186 × 10^-20 J

• 0.372 × 10^-20 J

• 0.56 × 10^-20 J

• 5.6 × 10^-20 J

The height of a water fall is 84 m. Assuming that the entire kinetic energy of falling water is converted into heat, the rise in temperature of the water will be

• 0.196°C

• 1.960°C

• 0.96°C

• 0.0196°C

If a body loses half of its velocity on penetrating 3 cm in a wooden block then how much will it penetrate more before coming to rest?

• 1 cm

• 2 cm

• 3 cm

• 4 cm

The minimum velocity (in ms^-1) with which a car driver must traverse a flat curve of radius 150 m and coefficient of friction to avoid skidding is

• 60

• 30

• 15

• 25

A steel ball is dropped from a height h and it makes a perfectly elastic collision with a horizontal plane. Following its initial release, it will make periodic motion with frequency

• $2\mathrm{\pi }\sqrt{\frac{\mathrm{g}}{\mathrm{h}}}$

• $2\mathrm{\pi }\sqrt{\frac{\mathrm{h}}{\mathrm{g}}}$

• $\frac{1}{2}\sqrt{\frac{\mathrm{g}}{2\mathrm{h}}}$

• $\frac{1}{2}\sqrt{\frac{2\mathrm{h}}{\mathrm{g}}}$

If the earth is treated as a sphere of radius R and mass M, its angular momentum about the axis of rotation with time period T is

• $\frac{{\mathrm{\pi MR}}^2}{\mathrm{T}}$

• $\frac{{\mathrm{MR}}^2\mathrm{T}}{2\mathrm{\pi }}$

• $\frac{2{\mathrm{\pi MR}}^2}{\mathrm{T}}$

• $\frac{4{\mathrm{\pi MR}}^2}{5\mathrm{T}}$

A child swinging on a swing in sitting position, stands up, then the time period of swing will

• increase

• decrease

• remain same

• increase if the child is long and decrease if the child is short

A mass of 10 g moving horizontally with a velocity of 100 cm/s strikes a pendulum bob of mass 10 g. The two masses stick together. The maximum height reached by the system now is (g = 10 m/s²)

• zero

• 5 cm

• 2.5 cm

• 1.25 cm

A particle of mass 10 g is executing simple harmonic motion with an amplitude of 0.5 m and periodic time of ($\mathrm{\pi }$/ 5) second. The maximum value of the force acting on the particle is

• 25 N

• 5 N

• 2.5 N

• 0.5 N