Properties of Solids and Liquids

Work done in increasing the size of a soap bubble

Work done in increasing the size of a soap bubble from a radius of 3 cm to 5 cm is nearly. (Surface tension of soap solution = 0.03 Nm-1)

  1. 0.2π mJ
  2. 0.4π mJ
  3. 2π mJ
  4. 4π mJ
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100 g of water is heated from 30°C to 50°C

100 g of water is heated from 30°C to 50°C ignoring the slight expansion of the water, the change in its internal energy is (specific heat of water is 4184 J/Kg/K)

  1. 2.1 kJ
  2. 4.2 kJ
  3. 8.4 kJ
  4. 84 kJ
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The pressure that has to be applied to the ends of a steel wire

The pressure that has to be applied to the ends of a steel wire of length 10 cm to keep its length constant when its temperature is raised by 100°C is: (For steel, Young’s modulus is 2×1011 N m–2 and coefficient of thermal expansion is 1.1×10-5 K-1)

  1. 2.2 × 106 Pa
  2. 2.2 × 107 Pa
  3. 2.2 × 108 Pa
  4. 2.2 × 109 Pa
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Water is flowing continuously from a tap having an internal diameter

Water is flowing continuously from a tap having an internal diameter 8×10-3 m. The water velocity as it leaves the tap is 0.4 ms-1. The diameter of the water stream at a distance 2×10-1 m below the tap is close to

  1. 7.5 × 10-3 m
  2. 9.6 × 10-3 m
  3. 3.6 × 10-3 m
  4. 5.0 × 10-3 m
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If mass-energy equivalence is taken into account

If mass-energy equivalence is taken into account, when water is cooled to form ice, the mass of water should

  1. first increase then decrease
  2. increase
  3. decrease
  4. remain unchanged
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A cylinder of height 20 m is completely filled with water. The velocity of efflux of water

A cylinder of height 20 m is completely filled with water. The velocity of efflux of water (in ms-1) through a small hole on the side wall of the cylinder near its bottom is

  1. 20
  2. 25.5
  3. 10
  4. 5
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The flow rate of water from a tap of diameter 1.25 cm is 0.48 L/min

The flow rate of water from a tap of diameter 1.25 cm is 0.48 L/min. The coefficient of viscosity of water is 10-3 Pa s. After sometime the flow rate is increased to 3 L/min. Characterize the flow for both the flow rates.

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If it takes 5 minutes to fill a 15 litre bucket from a water tap of diameter

If it takes 5 minutes to fill a 15 litre bucket from a water tap of diameter 2/√π cm then the Reynolds number for the flow is (density of water = 103 kg/m3 and viscosity of water = 10-3 Pa.s) close to:

  1. 5500
  2. 11,000
  3. 550
  4. 1100
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