A wooden block, with a coin placed on its top, floats in water as shown in the figure. The distances h and l are shown there. After sometime, the coin falls into the water. Then

• both l and h increase

• both l and h decrease

• l decreases and h increases

• l increases and h decreases

22.

A square wire frame of size L is dipped in a liquid. On taking out a membrane is formed. If the surface tension of liquid is T, then force acting on a frame will be

• 2T L

• 4T L

• 8T L

• 16T L

A 20 cm long capillary tube is dipped in water. The water rises up to 8 cm. If entire arrangement is put in a freely falling elevator, the length of water column in the capillary tube will be

• 4 cm

• 8 cm

• 10 cm

• 20 cm

A metal plate of area 10³ cm² rests on a layer of oil 6 mm thick. A tangential force of 10^-2 N is applied on it to move it with a constant velocity of 6 cms^-1. The coefficient of viscosity of the liquid is

• 0.1 poise

• 0.5 poise

• 0.7 poise

• 0.9 poise

Sixty four spherical rain drops of equal size are falling vertically through air with a terminal velocity 1.5 ms^-1 . If these drops coalesce to form a big spherical drop, then terminal velocity of big drop is

• 8 ms^-1

• 16 ms^-1

• 24 ms^-1

• 32 ms^-1

A cylinder of height 20 m is completely filled with water. The velocity of efflux of water (in ms^-1 ) through a hole on the side wall of the cylinder near its bottom, is

• 10

• 20

• 25.5

• 5

A liquid flows through a pipe of non-uniform cross-section. If A₁ and A₂ are the cross-sectional areas of the pipe at two points, the ratio of velocities of the liquid at these points will be

• A₁A₂

• $\frac{{\mathrm{A}}_1}{{\mathrm{A}}_2}$

• $\frac{{\mathrm{A}}_2}{{\mathrm{A}}_1}$

• $\frac{1}{{\mathrm{A}}_1{\mathrm{A}}_2}$

A particle executes simple harmonic motion between x = − A and x = + A. The time taken for it to go from O to A/ 2 is T₁ and to go from A/2 to A is T₂ . Then

• T₁ < T₂

• T₁ > T₂

• T₁ = T₂

• T₁ = 2T₂

A body executes simple harmonic motion. The potential energy (PE), kinetic energy (KE) and total energy (TE) are measured as a function of displacement y. Which of the following statements is true ?

• TE is zero when x = 0

• PE is maximum when x = 0

• KE is maximum when x = O

• KE is maximum when x is maximum

The equation of a wave is y = 5 sin $\left(\frac{\mathrm{t}}{0.04} - \frac{\mathrm{x}}{4}\right)$ where x is in cm and t in seconds. The maximum velocity of the wave will be

• 1 ms^-1

• 2 ms^-1

• 1.5 ms^-1

• 1.25 ms^-1