CBSE Class 11 Physics Mechanical Properties of Fluids Worksheet Set C

 

MECHANICAL PROPERTIES OF SOLIDS MECHANICAL PROPERTIES OF FLUIDS
AND THERMAL PROPERTIES

SECTION A CONCEPTUAL AND APPLICATION TYPE QUESTIONS

Question. Water is not used in thermometer because
(a) it sticks to glass
(b) its shows anamalous expansion
(c) both (a) and (b)
(d) neither (a) nor (b)

Answer: C

Question. Consider a 1 c.c. sample of air at absolute temperature T₀ at sea level and another 1 c.c. sample of air at a height where the pressure is one-third atmosphere. The absolute temperature T of the sample at the height is
(a) equal to T₀/3
(b) equal to 3/T₀
(c) equal to T₀
(d) cannot be determined in terms of T₀ from the above data

Answer: A

Question. An ideal fluid flows through a pipe of circular cross-section made of two sections with diameters 2.5 cm and 3.75 cm. The ratio of the velocities in the two pipes is
(a) 9 : 4
(b) 3 : 2
(c) √3: √2
(d) √2: √3

Answer: A

Question. 1 m³ water is brought inside the lake upto 200 metres depth from the surface of the lake. What will be change in the volume when the bulk modulus of elastically of water is 22000 atmosphere? (density of water is 1 × 10³ kg/m³ atmosphere pressure = 105 N/m² and g = 10 m/s²)
(a) 8.9 × 10^–3 m³
(b) 7.8 × 10^–3 m³
(c) 9.1 × 10^–4 m³
(d) 8.7 × 10^–4 m³

Answer: C

Question. Figure shows a capillary rise H. If the air is blown through the horizontal tube in the direction as shown then rise in capillary tube will be 

(a) = H
(b) > H
(c) < H
(d) zero

Answer: B

Question. The excess of pressure inside a soap bubble is twice the excess pressure inside a second soap bubble. The volume of the first bubble is n times the volume of the second where n is
(a) 0.125
(b) 0.250
(c) 1
(d) 2

Answer: A

Question. The level of water in a tank is 5m high. A hole of area 1 cm² is made in the bottom of the tank. The rate of leakage of water from the hole (g = 10 m/s²) is
(a) 10^–2 m³/s
(b) 10^–3 m³/s
(c) 10^–4 m³/s
(d) 103 m³/s

Answer: B

Question. A U tube with both ends open to the atmosphere, is partially filled with water. Oil, which is immiscible with water, is poured into one side until it stands at a distance of 10 mm above the water level on the other side. Meanwhile the water rises by 65 mm from its original level (see diagram). The density of the oil is
(a) 425 kg m^–3
(b) 800 kg m^–3
(c) 928 kg m^–3
(d) 650 kg m^–3

Answer: C

Question. An egg when placed in ordinary water sinks but floats when placed in brine. This is because
(a) density of brine is less than that of ordinary water
(b) density of brine is equal to that of ordinary water
(c) density of brine is greater than that of ordinary water
(d) None of these

Answer: C

Question. Toricelli’s theorem is used to find
(a) the velocity of efflux through an orifice.
(b) the velocity of flow of liquid through a pipe.
(c) terminal velocity
(d) critical velocity

Answer: A

Question. A vessel with water is placed on a weighing pan and it reads 600 g. Now a ball of mass 40 g and density 0.80 g cm^–3 is sunk into the water with a pin of negligible volume, as shown in figure keeping it sunk. The weighting pan will show a reading 

(a) 600 g
(b) 550 g
(c) 650 g
(d) 632 g

Answer: C

Question. Water flows in a stream line manner through a capillary tube of radius a, the pressure difference being P and the rate flow Q. If the radius is reduced to a/2 and the pressure is increased to 2P, the rate of flow becomes
(a) 4Q
(b) Q
(c) Q/2
(d) Q/8

Answer: D

Question. A liquid does not wet the sides of a solid, if the angle of contact is
(a) Zero
(b) Obtuse (more than 90°)
(c) Acute (less than 90°)
(d) 90° (right angle)

Answer: B

Question. A rain drop of radius 0.3 mm has a terminal velocity in air = 1 m/s. The viscosity of air is 8 × 10^–5 poise. The viscous force on it is
(a) 45.2 × 10^–4 dyne
(b) 101.73×10^–5 dyne
(c) 16.95 × 10^–4 dyne
(d) 16.95 × 10^–5 dyne

Answer: A

Question. Along a streamline,
(a) the velocity of a fluid particle remains constant
(b) the velocity of all fluid particles crossing a given position is constant
(c) the velocity of all fluid particles at a given instant is constant
(d) the speed of a fluid particle remains constant

Answer: B

Question. A man is sitting in a boat which is floating in pond. If the man drinks some water from the pond, the level of water in the pond will
(a) rise a little
(b) fall a little
(c) remain stationary
(d) none of these

Answer: C

Question. The reading of spring balance when a block is suspended from it in air is 60 newton. This reading is changed to 40 newton when the block is submerged in water. The specific gravity of the block must be therefore
(a) 3
(b) 2
(c) 6
(d) 3/2

Answer: A

Question. Horizontal tube of non-uniform cross-section has radii of 0.1 m and 0.05 m respectively at M and N for a streamline flow of liquid the rate of liquid flow is 
(a) continuously changes with time
(b) greater at M than at N
(c) greater at N than at M
(d) same at M and N

Answer: D

Question. In case A, when an 80 kg skydiver falls with arms and legs fully extended to maximize his surface area, his terminal velocity is 60 m/s. In Case B, when the same skydiver falls with arms and legs pulled in and body angled downward to minimize his surface area, his terminal velocity increases to 80 m/s. In going from Case A to Case B, which of the following statements most accurately describes what the skydiver experiences?
(a) F_{air resistance} increases and pressure P increases
(b) F_{air resistance} increases and pressure P decreases
(c) F_{air resistance} decreases and pressure P increases
(d) F_{air resistance} remains the same and pressure P increases

Answer: D

Question. Two liquids of densities d₁ and d₂ are flowing in identical capillary tubes uder the same pressure difference. If t₁ and t₂ are time taken for the flow of equal quantities (mass) of liquids, then the ratio of coefficient of viscosity of liquids must be
(a) d₁t₁/d₂t₂
(b) t₁/t₂
(c) d₂/ t₂ d₁/t₁
(d) √d₁t₁/d₂t₂

Answer: A

MECHANICAL PROPERTIES OF SOLIDS

1 What does the slope of stress Vs strain graph give?

2 Why are springs made of steel and not copper?

3 Stress and pressure are both forces per unit area. Then in what respect does stress differ from pressure?

4 Why the bridges are declared unsafe after long use?

5 If ‘S’ is stress and ‘Y’ is young’s modulus of the material of a wire, what is the energy stored in wire per unit volume in terms of ‘S’ and ‘Y’?

6 Represent graphically the variation of extension with load in an elastic body. On the graph mark: (a) Hooke’s law region (b) Elastic limit (c) Yield point. (d) Breaking point

7 Why Pillars and Columns are I shaped ?

8 Why thick steel ropes are made by braiding a number of thin steel wires?

9 Why any mountain on earth cannot have its height more than 10 km? Explain.

10 A wire is cut to half its original length (a) How would it affect the increase in length under a given load? (b) How does it affect the maximum load it can support without exceeding the elastic limit?

11 Which is more elastic, rubber or steel? Support your answer.

 

MECHANICAL PROPERTIES OF FLUIDS

1 Mention two applications of Pascal’s law .

2 Why mercury is used as a barometric liquid?

3 Write the equation of continuity for i) a compressible fluid ii) incompressible fluid.

4 Why shapes of aeroplanes and cars are streamlined ?

5 Why soldering flux is added with molten lead while soldering electrical circuits?

6 Why two holes are made to empty an oil tin?

7 How do insects run on the surface of water?

8 Why the blood pressure in humans is greater at the feet than at thebrain?

9 A person standing near a speeding train has a danger of fallingtowards the train. Why?

10 Why a small bubble rises slowly through a liquid whereas the biggerbubble rises rapidly?

11 Give expression for the Reynold’s number and show that it is a dimensional constant.

12 What is the mechanical advantage of hydraulic press / lift?

13 How ploughing of the soil helps in retaining the moisture of soil?

15 When air is blown between two balls suspended close to each other, they are attracted towards each other. Why?

16 What happens to the surface tension when some impurity is added to water?

17 How does the angle of contact of a liquid depends on temperature?

18 Why is it difficult to stop bleeding from a cut in human body at high altitudes?

19 Oil is sprinkled on sea waves to calm them. Why?

20 Draw velocity time graph for a steel sphere dropped in a highly viscous fluid in a broad and tall jar.

 

THERMAL PROPERTIES OF MATTER

1 Why a small gap is left between two sections of steel rail of railway tracks?

2 i)Why is water used as an effective coolant?
ii) Why is water used in hot water bottles?

3 Stainless steel cooking pans are preferred with extra copper bottom. Why?

4 Explain why a beaker filled with water at 4oC overflows if temperature is decreased or increased.

5 What kind of thermal conductivity and specific heat requirements would you specify for cooking utensils?

6 Explain why a beaker filled with water at 4oC overflows if temperature is decreased or increased.

7 Pendulum clocks generally run fast in winter and slow in summer. Why?

8 Why invar steel is used in pendulum clocks for making the pendulums?

9 Explain how the loss of heat due to three modes of heat transfer is minimized in a thermos flask.

10 Why pressure cookers are necessary for cooking at hill stations?

Please click on below link to download CBSE Class 11 Physics Mechanical Properties of Fluids Worksheet Set C