MCQ:Thrust , Presure,Buyoancy and Density (9th physics)

MCQ’s Based On Thrust , Presure,Buyoancy and Density

1. Units of pressure are :-

(a) N/m2                                  (b) m2/N

(c) Nm2                                   (d) Nm

2. Units of Relative Density are :-

(a) Kg/m3                    (b) Unit less

(c) Depends on the density of the substance

(d) Depend on the density of water

3. Pressure at a point in the liquid is

(a) Same in all directions                                 (b) Greater in the upward direction

(c) Grater in the downward direction (d) None of the Above

4. If the area of an object is less then the pressure acting on that object will be

(a) Less                                    (b) More

(c) Independent of area          (d) None of the above

5.  If cross – sectional area of an object is more than the pressure applied by the external force is :-

(a) Less                                    (b) More

(c) Remains same                    (d) None of the above.

6. Mass per unit volume of a substance is called

(a)Density                               (b)Relative density

(c)specific gravity                   (d)None

7. A buoyant force of 200 g wt. acts on a body dipped completely in water. If the apparent weight of body is 100 g wt., then its actual weight is

(a)200 g wt.                             (b)100 g wt.

(c)300 g wt.                             (d)None of these

8. If the weight of the floating body is equal to the buoyant force then body

(a)Sinks                                   (b)Rises

(c)Floats                                  (d) First floats and then sinks

9. When a body is placed in a liquid, the buoyant force experienced by it is equal to the

(a)weight of liquid displaced  (b)Density of the body

(c)volume of body                              (d)Density of liquid

10. A body immersed in a liquid will rise to the surface if the buoyant force acting on it is

(a)greater than its actual weight                      (b)less than its actual weight

(c)equal to its actual weight                (d)equal to Zero

11. When a body is submerged in a liquid, its weight

(a)Remains same                                             (b)Increases

(c)Decreases                                                    (d)Reduces to zero

12. A body weighing 200 g wt. is dipped in water. Its weight in water as indicated by the spring balance is 150 g wt. The buoyant force acting on the body is

(a)200 g wt                              (b)1000 g wt

(c)50 g wt                                (d)250 g wt

13. A body is floating in upright position in water. Then force of gravity and buoyant force acting on the body are

(a) In the same direction long the same line

(b) In opposite direction but along the same line

(c) At right angle to each other.

(d) In opposite to direction and from couple which turns and only anti-clockwise.

14. A body floats in vertical position, when its centre of buoyancy is

(a) Below C.G. of the body    (b) Above the C.G. of the body

(c) At some place where the C.G. of the body lies     (d) None of these.

15. In case of a body placed in liquid if the buoyant force is equal to its acutal weight, then its apparent weight

(a) Is equal to the actual weight                       (b) Is equal to buoyant force

(c) Is greater than its actual weight     (d) Is equal to zero

16. A block of ice is floating on water contained in a beaker. When all the ice melts, the level of water

(a)rises                         (b)falls

(c)remains unchanged (d)None

17. A boat floating in a tank is carrying passengers. If the passengers drink water, the water level of the tank

(a) rises                                                 (b) falls

(c) remains unchanged                        (d) depends upon the atmospheric pressure