List of top Physics Questions

Plot a graph showing the variation of current with voltage for the material GaAs. On the graph, mark the region where: (a) resistance is negative, and (b) Ohm's law is obeyed.
Find the temperature at which the resistance of a wire made of silver will be twice its resistance at $20^\circ$C. Take $20^\circ$C as the reference temperature and temperature coefficient of resistance of silver at $20^\circ$C = $4.0 \times 10^{-3\ \text{K}^{-1}$.}
Ge is doped with As. Due to doping,
The transition of electron that gives rise to the formation of the second spectral line of the Balmer series in the spectrum of hydrogen atom corresponds to:
The waves associated with a moving electron and a moving proton have the same wavelength \( \lambda \). It implies that they have the same :
A galvanometer of resistance $G\,\Omega$ is converted into an ammeter of range $0$ to $1\,A$. If the current through the galvanometer is $0.1%$ of $1\,A$, the resistance of the ammeter is:
A loop carrying a current I clockwise is placed in x - y plane, in a uniform magnetic field directed along z-axis. The tendency of the loop will be to:
In a full-wave rectifier, the current in each of the diodes flows for:
(iii) In a full-wave rectifier:
Ten capacitors, each of capacitance $1\,\mu F$, are connected in parallel to a source of $100\,V$. The total energy stored in the system is equal to:
What is meant by displacement current? A capacitor is being charged by a battery. Show that Ampere-Maxwell law justifies continuity and constancy of the current flowing in the circuit.
Determine the current in the \( 3 \, \Omega \) branch of a Wheatstone Bridge in the circuit shown in the figure.

A thin uniform rod (\(X\)) of mass \(M\) and length \(L\) is pivoted at a height \( \left(\dfrac{L}{3}\right) \) as shown in the figure. The rod is allowed to fall from a vertical position and lie horizontally on the table. The angular velocity of this rod when it hits the table top is ________. (\(g\) = gravitational acceleration) 

State Bohr’s postulates and derive the expression for the radius of the \( n^{\text{th}} \) orbit.
Derive the Lens Maker’s Formula for a thin convex lens.
Explain the principle and working of an AC Generator or a Transformer (including energy losses).
Explain the principle, construction, and derive the current sensitivity of a moving coil galvanometer.
Define Drift Velocity and establish its relation with electric current.
Derive the condition for a balanced Wheatstone Bridge.
Derive the expression for the capacitance of a parallel plate capacitor (with and without dielectric slab).
Derive the expression for Electric Field Intensity on the axial and equatorial line of a dipole.
State Gauss’s Theorem and use it to find the electric field due to an infinitely long charged wire or a thin spherical shell.
A solid sphere of mass $5$ kg and radius $10$ cm is kept in contact with another solid sphere of mass $10$ kg and radius $20$ cm. The moment of inertia of this pair of spheres about the tangent passing through the point of contact is ___________ kg$\cdot$m$^2$.
A spring of force constant $15\,\text{N/m}$ is cut into two pieces. If the ratio of their lengths is $1:3$, then the force constant of the smaller piece is ___ $\text{N/m}$.

The equivalent resistance between the points \(A\) and \(B\) in the given circuit is \[ \frac{x}{5}\,\Omega. \] Find the value of \(x\).