Solids Fluids

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)

0.2π mJ
0.4π mJ
2π mJ
4π mJ

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)

2.1 kJ
4.2 kJ
8.4 kJ
84 kJ

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)

2.2 × 10⁶ Pa
2.2 × 10⁷ Pa
2.2 × 10⁸ Pa
2.2 × 10⁹ Pa

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

7.5 × 10^-3 m
9.6 × 10^-3 m
3.6 × 10^-3 m
5.0 × 10^-3 m

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

first increase then decrease
increase
decrease
remain unchanged

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

20
25.5
10
5

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.

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:

5500
11,000
550
1100