Physics Test 20...

In a hydrogen atom, the electron moves around the nucleus in a circular orbit of radius 5 × 10⁻¹¹ m. Its time period is 1.5 × 10⁻¹⁶s. The current associated with the electron motion is (charge of electron is 1.6 × 10⁻¹⁹ C)

A cubical vessel open from top of side L is filled with a liquid of density ρ then the torque of hydrostatic force on a side wall about an axis passing through one of bottom edges is-

A certain ideal gas undergoes a polytropic process PV ⁿ = constant such that the molar specific heat during the process is negative. If the ratio of the specific heats of the gas be γ, then the range of values of n will be

A ball is projected from the bottom of an inclined plane of inclination 30^o, with a velocity of 30 m s⁻¹, at an angle of 30^o with the inclined plane. If g = 10 ms⁻², then the range of the ball on given inclined plane is

A transistor-oscillator using a resonant circuit with an inductor L (of negligible resistance) and a capacitor C in series produce oscillations of frequency f. If L is doubled and C is changed to 4C, the frequency will be

If the radius of the earth were to shrink by one percent and its mass remains the same, the acceleration due to gravity on the earth's surface would

A black body, at 200 K, is found to have maximum energy at a wavelength of 14 μm. When its temperature is raised to 1000 K, the wavelength at which maximum energy is emitted is

The time constant of charging of the capacitor shown in the diagram is

Spherical wavefronts shown in figure, strike a plane mirror. Reflected wavefronts will be as shown in

A simple pendulum has a time period T₁ when on the earth's surface and T₂ when taken to a height 2R above the earth's surface where R is the radius of the earth. The value of