NCERT Physics Class 11 Exemplar Ch 10 Mechanical Properties of Fluids Part 2 (For CBSE, ICSE, IAS, NET, NRA 2023)

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One or More Than One Answer

Q. 6 For a surface molecule

  1. the net force on it is zero.
  2. there is a net downward force.
  3. the potential energy is less than that of a molecule inside.
  4. the potential energy is more than that of a molecule inside.

Answer: (a) , (d)

Q. 7 Pressure is a scalar quantity because

(a) it is the ratio of force to area and both force and area are vectors.

(b) it is the ratio of the magnitude of the force to area.

(c) it is the ratio of the component of the force normal to the area.

(d) it does not depend on the size of the area chosen.

Answer: (c) , (d)

Q. 8 A wooden block with a coin placed on its top, floats in water as shown in Fig.

Coin over Wooden Block

The distance and are shown in the figure. After some time, the coin falls into the water. Then

(a) l decreases.

(b) h decreases.

(c) l increases.

(d) h increase.

Answer: (a) , (b)

Q. 9 With increase in temperature, the viscosity of

(a) gases decrease.

(b) liquids increase.

(c) gases increase.

(d) liquids decrease.

Answer: (c) , (d)

Q. 10 Streamline flow is more likely for liquids with

(a) high density.

(b) high viscosity.

(c) low density.

(d) low viscosity.

Answer: (b) , (c)