Physics Test - ...

An observer is moving towards a stationary source with 1/10 the speed of sound. The ratio of apparent frequency to real frequency is

The disc of a siren containing 60 holes rotates at a constant speed of 360 rpm. The emitted sound is in unison with a tuning fork of frequency

A police car horn emits sound at a frequency of 240 Hz when the car is at rest. If the speed of sound is 330 m/s, the frequency heard by an observer who is approaching the car at a speed of 11 m/s, is

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

Consider a train was moving along negative \(x\) direction with speed \(50 \mathrm{~km} / \mathrm{hr}\) and a boy walking inside that train with speed \(2 \mathrm{~km} / \mathrm{hr}\) towards positive \({x}\) direction, in this case, what will be the relative velocity of the boy with respect to the train.

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 5 V. 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,

Sodium surface is illuminated by ultraviolet and visible radiations, successively and the stopping potential is determined. This stopping potential is

The bob of a simple pendulum is a spherical hollow ball filled with water. A plugged hole near the bottom of the oscillating bob gets suddenly unplugged. During observation, till water is coming out, the time period of oscillation would

A uniform metre scale of length 1 m is balanced on a fixed semi-circular cylinder of radius 30 cm as shown in the figure. One end of the scale is slightly depressed and released. The time period (in seconds) of the resulting simple harmonic motion is 

(Take g = 10 ms^-2)

Two SHMs are respectively represented by y₁ = a sin (ωt - kx), and y₂ = b cos (ωt - kx). The phase difference between the two is:

The displacement y of a particle executing periodical motion is given by y = 4 cos² (t/2) sin (1000t). This expression may be considered to be a result of the superposition of how many independent harmonic motions?

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.)