List of top Physics Questions

In Young's double slit experiment, the intensity of light at a point on the screen is \( K \) unit for path difference \( \Delta \). What would be the intensity at a point if the path difference is \( \frac{\Delta}{4} \)?
If intensity of incident radiation in a photocell is increased, the stopping potential
In a parallel plate capacitor, the capacity can be increased by decreasing
The earth's atmosphere is divided into different layers. Out of these layers, ionosphere consists of
A mass \( M \) is suspended from a spring of negligible mass. The spring is pulled a little and then released so that the mass executes simple harmonic motion (S.H.M.) of period \( T \). If the mass is increased by \( m \), the time period becomes \( \frac{T}{3} \). What is the ratio \( \frac{M}{m} \)?
A heavy mass is attached at one end of a thin wire and whirled in a vertical circle. The chances of breaking the wire are maximum when
A ray of unpolarised light is incident on the glass surface of refractive index 1.73 at polarizing angle. The angle of refraction will be [Take \( \tan 60^\circ = 1.73 \)]
What is the magnifying power of a simple microscope of focal length 5 cm, if the image is formed at the distance of distinct vision?
Two rain drops falling through air have radii in the ratio 1:2. They will have terminal velocity in the ratio
A wheel is at rest in horizontal position. Its moment of inertia about vertical axis passing through its center is \( I \). A constant torque \( \tau \) acts on it for \( t \) seconds. The change in rotational kinetic energy is
Two short bar magnets 'A' and 'B' (having magnetic moments \( M_1 \) and \( M_2 \) respectively) are kept one above the other with their magnetic axes perpendicular to each other. If their resultant at a point on the axis of magnet 'A' is inclined at 45° with the axis of magnet 'A', then the ratio of magnetic moments \( \frac{M_2}{M_1} \) is
Two small drops of mercury each of radius \( R \) coalesce to form a large single drop. The ratio of the total surface energies before and after the change is
Two identical wires are vibrating in unison. If the tension in one of the wires is increased by 2%, five beats are produced per second by the two vibrating wires. The initial frequency of each wire is
Electron in Hydrogen atom first jumps from third excited state to second excited state and then from second excited state to first excited state. The ratio of the wavelengths \( \lambda_1 : \lambda_2 \) emitted in the two cases respectively is
Choose the correct statement. In conductors
Resultant of two vectors \( \vec{P} \) and \( \vec{Q} \) is of magnitude \( R_1 \). If the direction of \( \vec{Q} \) is reversed, the resultant is of magnitude \( R_2 \). The value of \( (R_1^2 + R_2^2) \) is \( \cos (\pi - \theta) = - \cos \theta \)
In cyclotron, the time taken by an ion to describe semicircular path in a dee is
In meter bridge experiment, to minimize an error due to contact resistance,
Two cars of masses \( m_1 \) and \( m_2 \) are moving in the circles of radii \( r_1 \) and \( r_2 \) respectively. Their angular speeds \( \omega_1 \) and \( \omega_2 \) are such that they both complete one revolution in the same time \( t \). The ratio of linear speed of \( m_1 \) to the linear speed of \( m_2 \) is
Magnetic field at the centre of a circular loop of area \( A \) is \( B \). The magnetic moment of the loop will be (\( \mu_0 \) = permeability of free space)
A body is projected vertically upwards from earth’s surface with velocity \( 2v_e \), where \( v_e \) is escape velocity from earth’s surface. The velocity when body escapes the gravitational pull is
A solid cylinder of mass \( M \) and radius \( R \) rolls down a smooth inclined plane about its own axis and reaches the bottom with velocity \( v \). The height of the inclined plane is
Above the curie temperature the susceptibility of a ferromagnetic substance varies
Two wires 'A' and 'B' of equal lengths are connected in left and right gaps of a meter bridge, respectively. The null point is obtained at 40 cm from the left end. Diameters of the wires 'A' and 'B' are in the ratio 3:1, the ratio of specific resistance of 'A' to that of 'B' is
A ball of mass \( m \) is attached to the free end of an inextensible string of length \( \ell \). Let \( T \) be the tension in the string. The ball is moving in a horizontal circular path about the vertical axis. The angular velocity of the ball at any particular instant will be