M.C.Q : Fluid Motion ( 1 to 1 0 )

LEVEL – I

1. A and B are two metallic pieces. They are fully immersed in water and then weighed. Now they show same loss of weight. The conclusion therefore is:

(A) A and B have same weight in air

(B) A and B have equal volumes

(C) The densities of the materials of A and B are the same

(D) A and B are immersed to the same depth inside water.

2. An ice cube contains a large air bubble. The cube is floating on the surface of water contained on a trough. What will happen to the water level, when the cube melts?

(A) It will remain unchanged

(B) It will fall

(C) It will rise

(D) First it will and then rise

3. In a hydraulic lift, used at a service station the radius of the large and small piston are in the ratio of 20 : 1. What weight placed on the small piston will be sufficient to lift a car of mass 1500 kg?

(A) 3.75Kg

(B) 37.5Kg

(C) 7.5Kg

(D) 75Kg

4. Water and mercury are filled in two cylindrical vessels upto same height. Both vessels have a hole in the wall near the bottom. The velocity of water and mercury coming out of the holes are v1 and v2respectively. Thus

(A) v1 = v2

(B) v1 = 13.6v2

(C) v1 = v2/13.6

(D) v1 = √(13.6v2)

5. An ice cube contains a glass ball. The cube is floating on the surface of water contained in a trough on the surface of water contained in a trough. What will happen to the water level, when the cube melts?

(A) It will remain unchanged

(B) It will fall

(C) It will rise

(D) First it will fall and then rise

6. A square hole of side length l is made at a depth of y and a circular hole is made at a depth of 4y from the surface of water in a water tank kept on a horizontal surface. If equal amount of water comes out of the vessel through the holes per second then the radius of the circular hole is equal to(r, l << y) :

(A) l / √2

(B) l / 2

(C) l / √π

(D) l / √2π

7. In the figure shown a liquid is flowing through a tube at the rate of 0.1 m3/sec. The tube is branched into two semi circular tubes of cross sectional area A/3 and 2A/3. The velocity of liquid at Q is (the cross-section of the main tube (A) = 10-2 m2 and VP = 20 m/sec.): (A) 5 m/sec

(B) 30 m/sec

(C) 35 m/sec

(D) None of these.

8. A small hole is made at a height of h’ = (1/√2 ) m from the bottom of a cylindrical water tank and at a depth of h = √2 m from the upper level of water in the tank. The distance, where the water emerging from the hole strikes the ground is: (A) 2√2m

(B) 1 m

(C) 2 m

(D) None of these.

9. The excess pressure inside one soap bubble is three time that inside a second soap bubble. The ratio of the volumes of the two bubbles

(A) 1/9

(B) 9/1

(C) 1/27

(D) 27/1

10. An air bubble of diameter 2 mm rises steadily through a solution of density 1750 kg/m3 at the rate of .35 cm/sec. Coefficient of viscosity of the solution is (Assume mass of the bubble to be negligible)

(A) 9 poise

(B) 6 poise

(C) 11 poise

(D) 4 poise