Physics Test - ...

A point source emits sound equally in all directions in a non-absorbing medium. Two points P and Q are at distances of 2 m and 3 m, respectively, from the source. The ratio of intensities of the waves at P and Q is

Directions: The following question contains 4 choices (A), (B), (C) and (D), out of which ONLY ONE is correct

In the experiment to determine the speed of sound using a resonance column,

In photoelectric effect, we assume that photon energy is proportional to its frequency and is completely absorbed by the electrons in metal. Then, the photoelectric current 

The threshold frequency for a metallic surface corresponds to an energy of 6.2 eV, and the stopping potential for a radiation incident on this surface is 5V. The incident radiation lies in :

A photoelectric cell is illuminated by a point source of light 1 m away. When the source is shifted to 2 m, then

The figure shows variation of photocurrent with anode potential for a photosensitive surface for three different radiations. Let I_a, I_b and I_c be the intensities and _a, _b and _c be the frequencies for the curves a, b and c, respectively. Then,

Which of the following statement is incorrect regarding transverse wave?

During an object falling from height, its weight remains ________.

The displacement of a particle in a periodic motion is given by \(\mathrm{y}=4 \cos ^{2}\left(\frac{\mathrm{t}}{2}\right) \sin (1000 \mathrm{t})\). This displacement may be considered as the result of superposition of \(\mathrm{n}\) independent harmonic oscillations. Here \(\mathrm{n}\) is:

A particle in SHM is described by the displacement equation x(t) = A cos (ωt + θ). If the initial (t = 0) position of the particle is 1 cm and its initial velocity is π cm/s, then what is its amplitude? (The angular frequency of the particle is πs^-1.)

Three identical spheres, each of mass \(1 \mathrm{~kg}\) are placed touching each other with their centres on a straight line. Their centres are marked \(\mathrm{P}, \mathrm{Q}\) and \(\mathrm{R}\) respectively. The distance of centre of mass of the system from \(P\) is:

For the given uniform square lamina ABCD whose centre is O,

When a disc rotates with uniform, angular velocity, which of the following is not true ?

A bird sitting on a high tension electric wire does not get electrocuted, because:

Escape velocity of a particle depends on its mass \(\mathrm{m}\) as: