CBSE
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
A piece of ice is floating in a jar containing water. When the ice melts, then the level of water
rises
falls
remains unchanged
rises or falls
Radius of an air bubble at the bottom of the lake is r and it becomes 2 r when the air bubble rises to the top surface of the lake. If P cm of water be the atmospheric pressure, then the depth ofthe lake is
2 P
8 P
4 P
7 P
A manometer connected to a closed tap reads 4.5 x 105 Pa. When the tap is opened the reading of the manometer falls to 4 x 105 Pa. Then the velocity of flow of water is
7 ms-1
8 ms-1
9 ms-1
10 ms-1
A beaker of radius 15 cm is filled with a liquid of surface tension 0.75 N/m. Force across an imaginary diameter on the surface of the liquid is
0.075 N
1.5 × 10-2 N
0.225 N
2.25 × 10-2 N