List of top Physics Questions

A point source is kept at the center of a spherically enclosed detector. If the volume of the detector is increased by 8 times, the intensity will

When a light of a given wavelength falls on a metallic surface the stopping potential for photoelectrons is $3.2\ \text{V}$. If a second light having wavelength twice of the first light is used, the stopping potential drops to $0.7\ \text{V}$. The wavelength of the first light is ________ m.

A uniform solid cylinder of length $L$ and radius $R$ has moment of inertia about its axis equal to $I_1$. A small co-centric cylinder of length $L/2$ and radius $R/3$ carved from it has moment of inertia about its axis equal to $I_2$. The ratio $I_1/I_2$ is ________.

A point charge $q = 1\,\mu\text{C}$ is located at a distance $2\,\text{cm}$ from one end of a thin insulating wire of length $10\,\text{cm}$ having a charge $Q = 24\,\mu\text{C}$, distributed uniformly along its length, as shown in the figure. Force between $q$ and wire is ________ N.

10 mole of an ideal gas is undergoing the process shown in the figure. The heat involved in the process from $ P_1 $ to $ P_2 $ is $ \alpha $ Joule $(P_1 = 21.7 \text{ Pa}, P_2 = 30 \text{ Pa}, C_v = 21 \text{ J/K mol}, R = 8.3 \text{ J/mol K})$. The value of $ \alpha $ is ________.

Five persons $P_1, P_2, P_3, P_4$ and $P_5$ recorded object distance ($u$) and image distance ($v$) using same convex lens having power $+5$ D as (25,96), (30,62), (35,37), (45,35) and (50,32) respectively. Identify correct statement.

In a meter bridge experiment to determine the value of unknown resistance, first the resistances $2\,\Omega$ and $3\,\Omega$ are connected in the left and right gaps of the bridge and the null point is obtained at a distance $l$ cm from the left end. Now, when an unknown resistance $x\,\Omega$ is connected in parallel to $3\,\Omega$, the null point is shifted by $10\,\text{cm}$ to the right. The value of $x$ is ________ $\Omega$.

The reading of the ammeter ($A$) in steady state in the following circuit (assuming negligible internal resistance of the ammeter) is ________ A.

The binding energy for the following nuclear reactions are expressed in MeV.
\[ {}^{3}_{2}\text{He} + {}^{1}_{0}\text{n} \rightarrow {}^{4}_{2}\text{He} + 20 \text{ MeV} \] \[ {}^{4}_{2}\text{He} + {}^{1}_{0}\text{n} \rightarrow {}^{5}_{2}\text{He} - 0.9 \text{ MeV} \] If $ X_3, X_4, X_5 $ denote the stability of $ {}^{3}_{2}\text{He}, {}^{4}_{2}\text{He} $ and $ {}^{5}_{2}\text{He} $, respectively, then the correct order is:

The velocity ($v$) – distance ($x$) graph is shown in the figure. Which graph represents acceleration ($a$) versus distance ($x$) variation of this system?

A flexible chain of mass $m$ hangs between two fixed points at the same level. The inclination of the chain with the horizontal at the two points of support is $30^\circ$. Considering the equilibrium of each half of the chain, the tension of the chain at the lowest point is ________.

Three parallel plate capacitors each with area $A$ and separation $d$ are filled with two dielectric ($k_1$ and $k_2$) in the following fashion. ($k_1>k_2$) Which of the following is true?

The fifth harmonic of a closed organ pipe is found to be in unison with the first harmonic of an open pipe. The ratio of lengths of closed pipe to that of the open pipe is $ \frac{5}{x} $. The value of $ x $ is ________.

Two identical circular loops $P$ and $Q$ each of radius $r$ are lying in parallel planes such that they have common axis. The current through $P$ and $Q$ are $I$ and $4I$ respectively in clockwise direction as seen from $O$. The net magnetic field at $O$ is:

A moving coil galvanometer of resistance $100\,\Omega$ shows a full scale deflection for a current of $1\,\text{mA}$. The value of resistance required to convert this galvanometer into an ammeter, showing full scale deflection for a current of $5\,\text{mA}$, is ________ $\Omega$.

Identify the correct truth table of the given logic circuit.

In case of vertical circular motion of a particle by a thread of length $ r $, if the tension in the thread is zero at an angle $30^\circ$ as shown in the figure, the velocity at the bottom point (A) of the vertical circular path is ( $ g $ = gravitational acceleration ).

A regular hexagon is formed by six wires each of resistance $ r \,\Omega $ and the corners are joined to the centre by wires of same resistance. If the current enters at one corner and leaves at the opposite corner, the equivalent resistance of the hexagon between the two opposite corners will be

In a vernier callipers, 50 vernier scale divisions are equal to 48 main scale divisions. If one main scale division = 0.05 mm, then the least count of the vernier callipers is ________ mm.

A soap bubble of surface tension $0.04\,\text{N/m}$ is blown to a diameter of $7\,\text{cm}$. If $(15000 - x)\,\mu\text{J}$ of work is done in blowing it further to make its diameter $14\,\text{cm}$ $(\pi = 22/7)$, then the value of $x$ is ________.

There are three co-centric conducting spherical shells $A$, $B$ and $C$ of radii $a$, $b$ and $c$ respectively $(c>b>a)$ and they are charged with charges $q_1$, $q_2$ and $q_3$ respectively. The potentials of the spheres $A$, $B$ and $C$ respectively are:

A cylindrical block of mass $M$ and area of cross section $A$ is floating in a liquid of density $\rho$ with its axis vertical. When depressed a little and released the block starts oscillating. The period of oscillation is ___.

A short bar magnet placed with its axis at $30^\circ$ with an external magnetic field of $800$ Gauss experiences a torque of $0.016\,\text{N m}$. The work done in moving it from most stable to most unstable position is $\alpha \times 10^{-3}\,\text{J}$. The value of $\alpha$ is ___.

Given below are two statements:
Statement I: For all elements, greater the mass of the nucleus, greater is the binding energy per nucleon.
Statement II: For all elements, nuclei with less binding energy per nucleon transform to nuclei with greater binding energy per nucleon.
Choose the correct answer.

Density of water at $4^\circ$C and $20^\circ$C are $1000\,\text{kg/m}^3$ and $998\,\text{kg/m}^3$ respectively. The increase in internal energy of $4\,\text{kg}$ of water when it is heated from $4^\circ$C to $20^\circ$C is ___ J.
(Specific heat capacity of water $= 4.2\,\text{J g}^{-1}\text{K}^{-1}$ and atmospheric pressure $=10^5\,\text{Pa}$)