Spheres of iron and lead having same mass are completely immersed in water. Density of lead is more than that of iron. Apparent loss of weight is w₁ for iron sphere and w₂ for lead sphere, Then $\frac{{\mathrm{w}}_1}{{\mathrm{w}}_2}$ is

• > 1

• = 1

• become 0 and 1

• = 0

A hot body is allowed to cool. The surrounding temperature is constant at 30°C. The takes time t₁ to cool from 70°C to 68°C and time t₂ to cool from 60°C to 59.5°C. Then

• t₂ = t₁

• t₂ = 2t₁

• ${\mathrm{t}}_2 = \frac{1}{2} {\mathrm{t}}_1$

• t₂ = 4t₁

A particle executes SHM with amplitude 0.2 m and time period 24 s. The time required it to move from the mean position to a point 0.1 m from the mean position is

• 12 s

• 2 s

• 8 s

• 3 s

The circular motion of a particle with constant speed is

• neither periodic nor SHM

• periodic but not SHM

• SHM but not periodic

• periodic and also SHM

15.

A, B and C are the three identical conductors but made from different materials. They are kept in contact as shown

              

Their thermal conductivities are K, 2K and $\frac{\mathrm{K}}{2}$. The free end of A is at 100°C and the free end of C is at 0°C. During steady state, the temperature of the junction of A and B is nearly

• 37°C

• 71°C

• 29°C

• 63°C

One mole of an ideal gas is taken from A to B, from B to C and then C and A and then the variation of its volume with temperature for that change is as shown. Its pressure is p₀, volume is V₀, then the internal energy is

• at A and B are equal

• at A is more than at B

• at C is less than at B

• at B is more than at A

Which ofthe following is incorrect?

• 'Diffraction' helps us to distinguish between sound wave and light wave.

• If the wave is longitudinal, it must be a mechanical wave.

• If the wave is mechanical, it may or may not be a transverse wave

• Mechanical waves cannot propagate in vacuum.

In the uniform electric field of E = 1 x 10⁴ NC^-1, an electron is accelerated from rest. The velocity of the electron when it has travelled a distance of 2 × 10^-2 m is nearly $\left(\frac{\mathrm{e}}{\mathrm{m}} \mathrm{of} \mathrm{electron} = 1.8 \times {10}^{-11} \mathrm{C} {\mathrm{kg}}^{-1}\right)$

• 8.5 × 10⁶ ms^-1

• 1.6 × 10⁶ ms^-1 

• 0.85 × 10⁶ ms^-1

• 0.425 × 10⁶ ms^-1

In this diagram, the PD between A and B is 60 V. The PD across 6 µF capacitor is

• 4 V

• 10 V

• 5 V

• 20 V

In this circuit, when certain current flows, the heat produced in 5 Ω is 4.05 J in a time t. The heat produced in 2 Ω coil in the same time interval is

• 2.02

• 5.76

• 1.44

• 2.88