Physics Test 62...

If a carrier waves C(t) = A sinω_c is being amplitude modulated by modulating wave (m)t = A sinω_mt Then the eg. of modulated wave [C_m(t)] and the modulation index are respectively.

A letter ‘A’ is constructed of a uniform wire with resistance 1.0 Ω per cm. The sides of the letter of 20 cm and the cross piece in the middle is 10 cm long. The apex angle is 60°. The resistance between the ends of the legs is close to:

An electric current is flowing through a circular coil of radius R. The ratio of the magnetic field at the center of the coil and that at a distance 2√2 from the center of the coil and on its axis is:

Two simple pendulums of length 1m and 4m respectively are both given small displacement in the same direction at the same instant. They will be again in phase after the shorter pendulum has completed number of oscillations equal to:

Light is incident from a medium into air at two possible angles of incidence (a) 20° and (b) 40°. In the medium light travels 3.0 cm in 0.2 ns. The ray will:

When two sound wave travel in the same direction in a medium, the displacements of a particle located at ‘x’ at time ‘t’ is given by:

y₁ = 0.05 cos (0.50 π x – 100 π t)

y₂ = 0.05 cos (0.46 π x – 92 π t)

where y₁, y₂ and x are in meters and t in seconds. The speed of sound in the medium is:

An engine approaches a hill with a constant speed. When it is at a distance of 0.9 km, it blows a whistle whose echo is heard by the driver after 5 seconds. If the speed of sound in air is 330 m/s, then the speed of the engine is:

Two balls of same mass and carrying equal charge are hung from a fixed support of length l. At electrostatic equilibrium, assuming that angles made by each thread is small, the separation, x between the balls is proportional to: