If the volume of a block of aluminium is decreased by 1%, the pressure (stress) on its surface is increased by (Bulk modulus of Al = 7.5 10¹⁰ Nm^-2)

• 7.5 × 10¹⁰ Nm^-2

• 7.5 × 10⁸ Nm^-2

• 7.5 × 10⁶ Nm^-2

• 7.5 × 10⁴ Nm^-2

22.

The excess pressure inside one soap bubble is three times that inside a second soap bubble, then the ratio of their surface areas is

• 1 : 9

• 1 : 3

• 3 : 1

• 1 : 27

The area of cross-section of one limb of an U-tube is twice that of other. Both the limbs contain mercury at the same level. Water is poured in the wider tube so that mercury level in it goes down by 1 cm. The height of water column is (density of water = 10³ kg m^-3, density of mercury = 13.6 x 10³ kg m^-3)

• 13.6 m

• 40.8 m

• 27.2 m

• 54.4 m

A bubble of 8 mole of helium is submerged at a certain depth in water. The temperature of water increases by 30°C. How much heat is added approximately to helium during expansion ?

• 4000 J

• 3000 J

• 3500 J

• 4500 J

The plots of intensity of radiation versus wavelength of three black bodies at temperatures T₁, T₂ and T₃ are shown. Then,

• T₃ > T₂ > T₁

• T₁ > T₂ > T₃

• T₂ > T₃ > T₁

• T₁ > T₃ > T₂

Three rods made of same material and having same cross-section are joined as shown in the figure. Each rod is of same length. The temperature at the junction of the three rods is

• 45°C

• 90°C

• 60°C

• 20°C

The p-V diagram of a gas undergoing a cyclic process (ABCDA) is shown in the graph where p is in units of Nm and V in cm. Identify the incorrect statement.

• 0.4 J of work is done by the gas from A to B.

• 0.2 J of work is done on the gas from C and D.

• Work is done by the gas in going from B to Cand on the gas from D to A.

• Net work done by the gas in one cycle is 0.2 J.

The period of a simple pendulum inside a stationary lift is T. The lift accelerates upwards with an acceleration of g/3. The time period of pendulum will be

• $\sqrt{2} \mathrm{T}$

• $\frac{\mathrm{T}}{\sqrt{2}}$

• $\frac{\sqrt{3}}{2} \mathrm{T}$

• $\frac{\mathrm{T}}{3}$

The amplitude of- SHM $\mathrm{y} = 2 \left( \sin 5\mathrm{\pi t} + \sqrt{2} \cos \mathrm{\pi t}\right)$ is

• 2

• $2\sqrt{2}$

• 4

• $2\sqrt{3}$

The total energy of a simple harmonic oscillator is proportional to

• square root of displacement

• velocity

• square of the amplitude

• amplitude