List of top Physics Questions

What is the fundamental frequency of an open organ pipe with length \( L \) and speed of sound \( v \)?
Consider the following logic circuit. The circuit consists of three gates: an AND gate, an OR gate, and a NOT gate. The inputs to the AND gate are \( A = 1 \) and \( B = 0 \). The output of the AND gate is fed into the input of the OR gate, which has another input \( C = 1 \). The output of the OR gate is then passed through a NOT gate. What is the final output of the circuit?
Rate of cooling of a body is \(0.2^\circ \text{C/min}\) when excess temperature is \(20^\circ \text{C}\). The proportionality constant \( k \) is:
The longest wavelength associated with the Paschen series is: $$ \text{(Given } R_H = 1.097 \times 10^7 \, \text{SI unit)}. $$ 
If \( n \) is the number density and \( d \) is the diameter of the molecule, then the average distance covered by a molecule between two successive collisions (i.e., mean free path) is represented by:
A light-emitting diode (LED) is fabricated using GaAs semiconductor material whose band gap is \( 1.42 \, \text{eV} \). The wavelength of light emitted from the LED is:

The logic performed by the circuit shown in the figure is equivalent to: 

A liquid is allowed to flow into a tube of truncated cone shape. Identify the correct statement:
In an a.c. circuit, voltage and current are given by: \[ V = 100 \sin(100t) \, \text{V} \quad \text{and} \quad I = 100 \sin\left(100t + \frac{\pi}{3}\right) \, \text{mA}. \] The average power dissipated in one cycle is:
A series LCR circuit is subjected to an AC signal of \( 200 \, \text{V}, 50 \, \text{Hz} \). If the voltage across the inductor (\( L = 10 \, \text{mH} \)) is \( 31.4 \, \text{V} \), then the current in this circuit is:
Two identical particles each of mass \( m \) go around a circle of radius \( a \) under the action of their mutual gravitational attraction. The angular speed of each particle will be:
"The height from Earth's surface at which acceleration due to gravity becomes \( g/4 \), where \( g \) is acceleration due to gravity on the surface of Earth and \( R \) is the radius of Earth?"
Eight equal drops of water are falling through air with a steady speed of \( 10 \, \text{cm/s} \). If the drops coalesce, the new velocity is:
An ice cube has a bubble inside. When viewed from one side, the apparent distance of the bubble is \( 12 \, \text{cm} \). When viewed from the opposite side, the apparent distance of the bubble is \( 4 \, \text{cm} \). If the side of the ice cube is \( 24 \, \text{cm} \), the refractive index of the ice cube is:
A big drop is formed by coalescing 1000 small droplets of water. The surface energy will become:
Water is flowing through a horizontal pipe in streamline flow. At the narrowest part of the pipe:
In an unbiased \( p\)-\( n \) junction, electrons diffuse from \( n\)-region to \( p\)-region because:
Point charge of \( 10 \, \mu C \) is placed at the origin. At what location on the X-axis should a point charge of \( 40 \, \mu C \) be placed so that the net electric field is zero at \( x = 2 \, \text{cm} \) on the X-axis?
A particle performs simple harmonic motion with amplitude \( A \). Its speed is tripled at the instant that it is at a distance \( \frac{2A}{3} \) from the equilibrium position. The new amplitude of the motion is:
The potential energy of a particle performing linear S.H.M is \( 0.1 \pi^2 x^2 \) joules. If the mass of the particle is \( 20 \, \mathrm{g} \), find the frequency of S.H.M:
The time period of SHM is \( 2 \, \mathrm{s} \) with mass \( m \). If an additional mass of \( 40 \, \mathrm{g} \) is added, the time period increases by \( 3 \, \mathrm{s} \). What is \( m \) (in grams)?
Find the ratio of K.E. and P.E. when a particle performs SHM when it is at \( \frac{1}{n} \) times of its amplitude from the mean position.
A particle is executing Simple Harmonic Motion (SHM). The ratio of potential energy and kinetic energy of the particle when its displacement is half of its amplitude will be:
The mass of proton, neutron, and helium nucleus are respectively \( 1.0073 \, \text{u}, 1.0087 \, \text{u}, \, 4.0015 \, \text{u} \). The binding energy of the helium nucleus is:
In a coil, the current changes from \( -2 \, \text{A} \) to \( +2 \, \text{A} \) in \( 0.2 \, \text{s} \) and induces an emf of \( 0.1 \, \text{V} \). The self-inductance of the coil is: