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8. Two capillaries made of same material but of different radii are dipped in a liquid. The rise of liquid in one capillary is 2.2 cm and that in the other is 6.6 cm. The ratio of their radii is

(a) 9 : 1 (b) 1 : 9 (c) 3 : 1 (d) 1 : 3 Ans. c (11)

7. Two capillary tubes P and Q are dipped in water. The height of water level in capillary P is 2/3 to the height in Q capillary. The ratio of their diameters is

(a) 2 : 3 (b) 3 : 2 (c) 3 : 4 (d) 4 : 3 Ans. b (10)

1. If pressure at half the depth of a lake is equal to 2/3 pressure at the bottom of the lake then what is the depth of the lake

(a) 10 m (b) 20 m (c) 60 m (d) 30 m Answer-b (7)

17. A student plots a graph from his reading on the determination of Young’s modulus of a metal wire but forgets to label. The quantities on X and Y axes may be respectively

(a) Weight hung and length increased (b) Stress applied and length increased (c) Stress applied and strain developed (d) Length increased and weight hung Answer-c (5)

16. The diagram shows the change x in the length of a thin uniform wire caused by the application of stress F at two different temperatures

16. The diagram shows the change x in the length of a thin uniform wire caused by the application of stress F at two different temperatures T1 and T2. The variations shown suggest that (a) T1 > T2 (b) T1 < T2 …

15. Which one of the following is the Young’s modulus (in N/m2) for the wire having the stress-strain curve shown in the figure

(a) 9×1011 (b) 8×1011 (c) 10×1011 (d) 2×1011 Answer-d (6)

6. It is not possible to write directly on blotting paper or newspaper with ink pen

(a) Because of viscosity (b) Because of inertia (c) Because of friction (d) Because of capillarity Ans. d (44)

12. The potential energy U between two molecules as a function of the distance X between them has been shown in the figure. The two molecules are

(a) Attracted when x lies between A and B and are repelled when X lies between B and C (b) Attracted when x lies between B and C and are repelled when X lies between A and B (c) Attracted …

11. The graph shows the behaviour of a length of wire in the region for which the substance obeys Hook’s law. P and Q represent

(a) P = applied force, Q = extension (b) P = extension, Q = applied force (c) P = extension, Q = stored elastic energy (d) P = stored elastic energy, Q = extension Answer-c (7)

2. A large number of water drops each of radius r combine to have a drop of radius R. If the surface tension is T and the mechanical equivalent of heat is J, then the rise in temperature will be

(a) 2T/rJ (b) 3T/RJ (c) 3T/J[(1/R )-(1/R)] (d) 2T/J[(1/r)-(1/R)] Ans. c (30)

6. The diagram shows a force-extension graph for a rubber band. Consider the following statementsI. It will be easier to compress this rubber than expand it II. Rubber does not return to its original length after it is stretched III. The rubber band will get heated if it is stretched and released Which of these can be deduced from the graph

(a) III only (b) II and III (c) I and III (d) I only Explanation-a (9)

5. The strain-stress curves of three wires of different materials are shown in the figure. P, Q and R are the elastic limits of the wires. The figure shows that

(a) Elasticity of wire P is maximum (b) Elasticity of wire Q is maximum (c) Tensile strength of R is maximum (d) None of the above is true Answer-d (4)

1. There is a horizontal film of soap solution. On it a thread is placed in the form of a loop. The film is pierced inside the loop and the thread becomes a circular loop of radius R. If the surface tension of the loop be T, then what will be the tension in the thread

(a) πR2/T (b) πR2T (c) 2πRT (d) 2RT Ans. d (21)

2. Due to capillary action, a liquid will rise in a tube, if the angle of contact is

(a) Acute (b) Obtuse (c) 90° (d) Zero Ans. a (3)

1. When two capillary tubes of different diameters are dipped vertically, the rise of the liquid is

(a) Same in both the tubes (b) More in the tube of larger diameter (c) Less in the tube of smaller diameter (d) More in the tube of smaller diameter Ans. d (35)

4. In a surface tension experiment with a capillary tube water rises upto 0.1 m. If the same experiment is repeated on an artificial satellite, which is revolving around the earth, water will rise in the capillary tube upto a height of

(a) 0.1 m (b) 0.2 m (c) 0.98 m (d) Full length of the capillary tube Ans. (d) In the satellite, the weight of the liquid column is zero. So the liquid will rise up to the top of the …

3. An air bubble in a water tank rises from the bottom to the top. Which of the following statements are true

(a) Bubble rises upwards because pressure at the bottom is less than that at the top. (b) Bubble rises upwards because pressure at the bottom is greater than that at the top. (c) As the bubble rises, its size increases …

9. The adjacent graph shows the extension

The adjacent graph shows the extension (Δl) of a wire of length 1m suspended from the top of a roof at one end with a load W connected to the other end. If the cross sectional area of the wire …

8. The load versus elongation graph for four wires of the same material is shown in the figure. The thickest wire is represented by the line

(a) OD (b) OC (c) OB (d) OA Answer-a (12)

13. The value of force constant between the applied elastic force F and displacement will be

(a) √3 (b) 1/√3 (c) 1/2 (d) √3/2 Answer-b (5)

7. The stress versus strain graphs for wires of two materials A and B are as shown in the figure.

The stress versus strain graphs for wires of two materials A and B are as shown in the figure. If Y1 and Y2 are the Young ‘s modulii of the materials, then (a) YB = 2YA (b) YA …

2. Assertion : It is better to wash the clothes in cold soap solution. Reason : The surface tension of cold solution is more than the surface tension of hot solution.

Read the assertion and reason carefully to mark the correct option out of the options given below: (a) If both assertion and reason are true and the reason is the correct explanation of the assertion. (b) If both assertion and …

3. In the above graph, point B indicates

(a) Breaking point (b) Limiting point (c) Yield point (d) None of the above Answer-c (12)

2. A graph is shown between stress and strain for a metal. The part in which Hooke’s law holds good is

(a) OA (b) AB (c) BC (d) CD Answer-a (8)

3. Which graph represents the variation of surface tension with temperature over small temperature ranges for water

Ans. b (7)

1. The graph shown was obtained from experimental measurements of the period of oscillations T for different masses M placed in the scale pan on the lower end of the spring balance. The most likely reason for the line not passing through the origin is that the

(a) Spring did not obey Hooke’s Law (b) Amplitude of the oscillations was too large (c) Clock used needed regulating (d) Mass of the pan was neglected Answer-d (5)

2. A soap bubble is blown with the help of a mechanical pump at the mouth of a tube. The pump produces a certain increase per minute in the volume of the bubble, irrespective of its internal pressure. The graph between the pressure inside the soap bubble and time t will be-

Ans. a (12)

1. The correct curve between the height or depression h of liquid in a capillary tube and its radius is

Ans. b (14)

12. Assertion : Sterss is the internal force per unit area of a body. Reason : Rubber is less elastic than steel.

(a) If both assertion and reason are true and the reason is the correct explanation of the assertion. (b) If both assertion and reason are true but reason is not the correct explanation of the assertion. (c) If assertion is …