Consider the Doppler effect in two cases. In the first case, an observer moves towards a stationary source of sound with a speed of $$50 \mathrm{~m} / \mathrm{s}$$. In the second case, the observer is at rest and the source moves towards the observer with the same speed of $$50 \mathrm{~m} / \mathrm{s}$$. Then the frequency heard by the observer will be

[velocity of sound in air $$=330 \mathrm{~m} / \mathrm{s}$$.]

According to Curie's law in magnetism, the correct relation is ( $$\mathrm{M}=$$ magnetization in paramagnetic sample, $$\mathrm{B}=$$ applied magnetic field, $$\mathrm{T}=$$ absolute temperature of the material, $$\mathrm{C}=$$ curie's constant)

A double convex air bubble in water behaves as

Three liquids have same surface tension and densities $$\rho_1, \rho_2$$, and $$\rho_3\left(\rho_1>\rho_2>\rho_3\right)$$. In three identical capillaries rise of liquid is same. The corresponding angles of contact $$\theta_1, \theta_2$$ and $$\theta_3$$ are related as