List of top Physics Questions

The coordinates of the centre of mass of a uniform L-shaped plate of mass 3 kg shown in the figure is:

 

A circular well of diameter \( 2 \, \text{m} \) has water up to the ground level. If the bottom of the well is at a depth of \( 14 \, \text{m} \), the time taken in seconds to empty the well using a \( 1.4 \, \text{kW} \) motor is (Acceleration due to gravity = \( 10 \, \text{m/s}^2 \))
If a force of \( (6x^2 - 4x) \, \text{N} \) acts on a body of mass 10 kg, then the work to be done by the force in displacing the body from \( x = 2 \, \text{m} \) to \( x = 4 \, \text{m} \) is
Two blocks A and B of masses 2 kg and 4 kg respectively are kept on a rough horizontal surface. If same force of 20 N is applied on each block, then the ratio of the accelerations of the blocks A and B is (Coefficient of kinetic friction between the surface and the blocks is 0.3 and acceleration due to gravity = \(10 \operatorname{ms}^{-2}\))
Water flowing through a pipe of area of cross-section \( 2 \times 10^{-3} \, \text{m}^2 \) hits a vertical wall horizontally with a velocity of \( 12 \, \text{m/s} \). If the water does not rebound after hitting the wall, then the force acting on the wall due to water is
A particle moving along a straight line covers the first half of the distance with a speed of \( 3 \, \text{m/s} \), the other half of the distance is covered in two equal time intervals with speeds of \( 4.5 \, \text{m/s} \) and \( 7.5 \, \text{m/s} \) respectively, then the average speed of the particle during the motion is
If a stone thrown vertically upwards from a bridge with an initial velocity of \(5 \operatorname{ms}^{-1}\), strikes the water below the bridge in a time of 3 s, then the height of the bridge above the water surface is (Acceleration due to gravity = \(10 \operatorname{ms}^{-2}\))
If the equation for the velocity of a particle at time 't' is \(v = at + \frac{b}{t+c}\), then the dimensions of a, b, c are respectively
One of the two identical capacitors having the same capacitance C, is charged to a potential \(V_1\) and the other is charged to a potential \(V_2\). If they are connected with their like plates together, then the decrease in the electrostatic potential energy of the combined system is
In Young's double-slit experiment, if the distance between the slits is increased to 3 times its initial distance, then the ratio of initial and final fringe widths is.
In a Carnot engine, if the absolute temperature of the source is \( 25% \) more than the absolute temperature of the sink, then the efficiency of the engine is
If a heat engine and a refrigerator are working between the same two temperatures \(T_1\) and \(T_2\) (\(T_1>T_2\)), then the ratio of efficiency of heat engine to coefficient of performance of refrigerator is
A force \( F \) is applied on a body of mass \( m \) so that the body starts moving from rest. The power delivered by the force at time \( t \) is proportional to:
The equations for the displacements of two particles in simple harmonic motion are \( y_1 = 0.1\sin\left(100\pi t + \frac{\pi}{3}\right) \) and \( y_2 = 0.1\cos(\pi t) \) respectively. The phase difference between the velocities of the two particles at a time \( t = 0 \) is
A short bar magnet is placed in a uniform magnetic field of $2~\text{T}$ such that the axis of the magnet makes an angle of $45^\circ$ with the field. If the torque acting is $0.36~\text{Nm}$, the magnetic moment of the magnet is
A horizontal telegraph wire of length $30~\text{m}$ fell from a height of $20~\text{m}$. If resistance is $40~\Omega$ and horizontal component of Earth’s magnetic field is $2 \times 10^{-5}~\text{T}$, the induced current is
In an LCR series circuit, if the potential differences across inductor, capacitor, and resistor are $60~\text{V}$, $30~\text{V}$, and $40~\text{V}$ respectively, then the net voltage applied to the circuit is
A plane EM wave of frequency $25~\text{MHz}$ propagates in vacuum. If electric field is $6.3~\text{V/m}$, then magnitude of magnetic field is
When a sphere is taken to the bottom of a sea of depth $1~\text{km}$, it contracts in volume by $0.01%$. Then the bulk modulus of the material of the sphere is (Acceleration due to gravity = $10~\text{m/s}^2$)
In amplitude modulation of waves, the maximum amplitude is $30~\text{mV}$ and minimum amplitude is $5~\text{mV}$, then the modulation index is
A transistor works as an amplifier when
If five logic gates are connected as shown in the figure, then the values of $y_1$, $y_2$, and $y_3$ are respectively
logic gates
The difference between the frequencies of the first and second Lyman lines of hydrogen atom is (R - Rydberg constant and c - speed of light in vacuum)
If the half-life of a radioactive element is $12.5$ hours, then the time taken to disintegrate $256~g$ of the substance into $1~g$ is (in hours)
A particle of mass $8~\mu g$ collides with another stationary particle of mass $4~\mu g$. If the collision is perfectly elastic and one dimensional, the ratio of de Broglie wavelengths after collision is