Physics Test 10...

The height at which the acceleration due to gravity decreases by 36% of its value on the surface of the earth is :

(Assume radius of the earth is R)

Two wires, one of steel (Y_steel = 2 × 10¹¹ N/m²) and the other of copper (Y_Cu = 10¹¹ N/m²) have same length and radii. If on applying a force F, the length of first wire increases by ℓ₀, then force required to increase the length of second wire by same amount is :-

There are two identical small holes of area of cross-section a on the opposite sides of a tank containing a liquid of density ρ. The difference in height between the holes is h. Tank is resting on a smooth horizontal surface. Horizontal force which will have to be applied on the tank to keep it in equilibrium is– 

Two drops of equal radius are falling through air with a steady velocity of 5 cm/s. If the two drops coalesce, then its terminal velocity will be –

The total energy of a simple harmonic oscillator is proportional to :-

The time period of second's pendulum is 2 sec. The spherical bob which is empty from inside has a mass of 50 gm. This is now replaced by another solid bob of same radius but having different mass of 100 gm. the new time period will be :-

A heavy rope is suspended from a rigid support. A wave pulse is set up at the lower end; then :-

A sound has an intensity of 2 × 10^–8 W/m². Its intensity level (in decibel) is : (log₁₀ 2 = 0.3) :-

are superposed on each other. The resulting amplitude and phase are respectively:

A cylinder of radius R made of material thermal conductivity K₁ is surrounded by a cylinderical shell of inner radius 2R made of material of thermal conductivity K₂. The two ends of combined system are maintained at two different temperature. There is no loss of heat & system is in steady state, calculate effective thermal conductivity of system :-