List of top Physics Questions

For a transistor, \( \alpha \) and \( \beta \) are given as \( \alpha = \frac{I_C}{I_E} \) and \( \beta = \frac{I_C}{I_B} \). Then the correct relation between \( \alpha \) and \( \beta \) will be:

A Carnot engine has an efficiency of 50%. If the temperature of the sink is reduced by \( 40^\circ C \), its efficiency increases by 30%. The temperature of the source will be:

Alternating current cannot be measured by a D.C. ammeter because
An ideal gas is expanding such that \( P T^3 = {constant} \). The coefficient of volume expansion of the gas is:

A particle of mass $ M $ originally at rest is subjected to a force whose direction is constant but magnitude varies with time according to the relation $ F = F_0 \left[ 1 - \left( \frac{t - T}{T} \right)^2 \right] $ 
where $ F_0 $ and $ T $ are constants. The force acts only for the time interval $ 2T $. The velocity $ v $ of the particle after time $ 2T $ is:

In the circuit shown in the figure, the total charge is \( 750 \, \mu C \) and the voltage across capacitor \( C_2 \) is \( 20 \, {V} \). Then the charge on capacitor \( C_2 \) is:
 

Two light beams of intensities in the ratio of 9 : 4 are allowed to interfere. The ratio of the intensity of maxima and minima will be:
The magnetic moment of an electron (e) revolving in an orbit around nucleus with an orbital angular momentum is given by:
Which is deflected by the magnetic field?
Following are expressions for four plane simple harmonic waves $$ y_1 = A \cos 2 \pi \left( n_1 t + \frac{x}{\lambda_1} \right), \quad y_2 = A \cos 2 \pi \left( n_1 t + \frac{x}{\lambda_1} + \pi \right), \quad y_3 = A \cos 2 \pi \left( n_2 t + \frac{x}{\lambda_2} \right), \quad y_4 = A \cos 2 \pi \left( n_2 t - \frac{x}{\lambda_2} \right) $$ The pairs of waves which will produce destructive interference and stationary waves respectively in a medium, are 
The root mean square speed of smoke particles of mass \( 5 \times 10^{-17} \) kg in their Brownian motion in air at NTP is approximately. (Given \( k = 1.38 \times 10^{-23} \, {JK}^{-1} \))
The focal length \( f \) is related to the radius of curvature \( r \) of the spherical convex mirror by:
Which of the following figure represents the variation of \( \ln \left( \frac{R}{R_0} \right) \) with \( \ln A \) (If \( R \) is the radius of a nucleus and \( A \) is its mass number)?

If a charge \( q \) is placed at the centre of a closed hemispherical non-conducting surface, the total flux passing through the flat surface would
 

The equation of a particle executing simple harmonic motion is given by \[ x = \sin \pi \left( t + \frac{1}{3} \right) \, {m}. \] At \( t = 1 \, {s} \), the speed of particle will be (Given \( \pi = 3.14 \)):
The equation \(z^2+\bar{z}^2=4\) in the complex plane (where \(\bar{z}\) is the complex conjugate of z) represents
A rocket (S') moves at a speed \(\frac{c}{2}\)m/s along the positive x-axis, where c is the speed of light. When it crosses the origin, the clocks attached to the rocket and the one with a stationary observer (S) located at x = 0 are both set to zero. If S observes an event at (x, t), the same event occurs in the S' frame at
Consider a classical ideal gas of N molecules in equilibrium at temperature T. Each molecule has two energy levels, -∈ and ∈. The mean energy of the gas is
At a temperature T, let \(\beta\) and \(\kappa\) denote the volume expansivity and isothermal compressibility of a gas, respectively. Then \(\frac{\beta}{\kappa}\) is equal to
The resultant of the binary subtraction 1110101-0011110 is
Consider a particle trapped in a three-dimensional potential well such that U(x, y, z) = 0 for 0 ≤ x ≤ a, 0 ≤ y ≤ a, 0 ≤ z≤a and U(x, y, z) = ∞ everywhere else. The degeneracy of the 5th excited state is
A particle of mass m and angular momentum L moves in space where its potential energy is U(r) = kr2 (k > 0) and r is the radial coordinate.
If the particle moves in a circular orbit, then the radius of the orbit is
Consider a two-dimensional force field
\(\overrightarrow{F}(x,y) = (5x^2 + ay^2 + bxy)\hat{x} + (4x^2 + 4xy + y^2) \hat{y}\).
If the force field is conservative, then the values of a and b are
Consider an electrostatic field \(\overrightarrow{E}\) in a region of space. Identify the INCORRECT statement.
Which one of the following figures correctly depicts the intensity distribution for Fraunhofer diffraction due to a single slit? Here, x denotes the distance from the centre of the central fringe and I denotes the intensity.