List of top Physics Questions asked in Assam Combined Entrance Examination

Four closed surfaces and corresponding charge distributions are shown below. The respective electric fluxes through the surfaces \( S_1, S_2, S_3, S_4 \) are \( \Phi_1, \Phi_2, \Phi_3, \Phi_4 \). Then, which of the following is correct?
The dimension of force constant is
Two very long, straight, and insulated wires are kept at a 90° angle from each other in the x-y plane as shown in the figure. These wires carry equal currents of magnitude \( I \), whose directions are shown in the figure. The net magnetic field at point P will be:
1 gm of ice at 0°C is mixed with 1 gm of water at 100°C. At thermal equilibrium, the temperature of the mixture will be:
Consider a viscous fluid having uniform density \( \rho \) and coefficient of viscosity \( \eta \). Two solid spheres with radius \( R_1 \) and \( R_2 \) fall into this liquid and acquire terminal velocities of \( V \) and \( 8V \) respectively. If the densities of the two spheres are \( 2\rho \) and \( 3\rho \) respectively, then \( R_1 \) is equal to \( R_2 \)?
At temperature \( T \), the probability of ideal gas molecules with mass \( m \) having speed \( v \) is given by \( P(v) \). Two quantities \( I_1 \) and \( I_2 \) are defined in terms of \( P(v) \) as follows:
\[ I_1 = \int_0^\infty P(v) v^3 \, dv \quad \text{and} \quad I_2 = \int_0^\infty P(v) v \, dv \] Which of the following relationship is true?
In a Doppler effect experiment, initially an observer and the source are moving towards each other with equal speeds. The observed frequency in this case is found to be \( f_0 \). The observed frequency once they cross each other is found to be \( f' \). If \( f \) is the frequency at the source, \( f' \) is equal to:
Consider two radioactive materials A and B. When A decays into 6.25 percent of its original amount, B decays into 25 percent of its original amount. The ratio of their decay constants \( \lambda_A \) and \( \lambda_B \) is:
The ratio of specific heats \( \frac{C_P}{C_V} \) in terms of degrees of freedom (n) is given by:
A block of mass 300 g is kept stationary on a smooth inclined plane by applying a minimum horizontal force \( F = \sqrt{a} \, N \) as shown in the figure. The value of \( a \) is (Take \( g = 10 \, \text{m/s}^2 \)):
A pulse of light of duration 50 ns is absorbed completely by a small object initially at rest. Power of the pulse is 60 mW and speed of light is \( 3 \times 10^8 \) m/s. The final momentum of the object is:
In the uranium radioactive series the initial nucleus is \(^{238}U\) and the final nucleus is \(^{206}Pb\). When the uranium nucleus decays to lead, the number of \(\alpha\)-particles and \(\beta\)-particles emitted respectively are:
A transverse wave is described by the equation \( y = A \sin \left( 2 \pi \left( \frac{r}{\lambda} - \frac{t}{T} \right) \right) \). The maximum particle velocity is equal to four times the wave velocity if:
A series R-C combination is connected to an AC voltage of angular frequency \( \omega = 1000 \) rad/s. If the impedance of the RC circuit is \( R/\sqrt{2} \), the time constant (in milliseconds) of the circuit is:
A piece of copper and another of germanium are cooled from room temperature to 100K. The resistance of