List of top Physics Questions

If the unit of force and length be each increased by four times, then the unit of energy is increased by

A solid body of constant heat capacity $1 \,J/?C$ is being heated by keeping it in contact with reservoirs in two ways : (i) Sequentially keeping in contact with $2$ reservoirs such that each reservoir supplies same amount of heat. (ii) Sequentially keeping in contact with $8$ reservoirs such that each reservoir supplies same amount of heat. In both the cases body is brought from initial temperature $100^{\circ}C$ to final temperature $200^{\circ}C$. Entropy change of the body in the two cases respectively is :

A man of mass \(100 \,kg\). is standing on a platform of mass \(200 \,kg\). Which is kept on a smooth ice surface. If the man starts moving on the platform with a speed \(30 \,m/sec\) relative to the platform then calculate with what velocity relative to the ice the platform will recoil?

Which of the following must be known in order to determine the power output of an automobile?

Three resistors $1\,\Omega , 2\,\Omega$ and $3\,\Omega $ are connected to form a triangle. Across $3\,\Omega$ resistor a $3\,V$ battery is connected. The current through $3\,\Omega$ resistor is

In a common emitter amplifier the input signal is applied across

Charge passing through a conductor of cross-section area $A=0.3 \,m ^{2}$ is given by $q=3 t^{2}+5 t+2$ in coulomb, where $t$ is in second. What is the value of drift velocity at $t=2 s ?$ (Given, $\left.n=2 \times 10^{25} / \,m ^{3}\right)$

$A$ and $B$ are two metals with threshold frequencies $1.8 \times 10^{14}\, Hz$ and $2.2 \times 10^{4}\, Hz$ Two identical photons of energy $0.825 \,eV$ each are incident on them. Then photoelectrons are emitted by (Take $\left.h=6.6 \times 10^{-34} \,J - s \right)$

Two capacitors of capacities $1 \, \mu F$ and $C \, \mu F$ are connected in series and the combination is charged to a potential difference of $120 \,V$. If the charge on the combination is $80 \, \mu C$, the energy stored in the capacitor of capacity $C$ in $\mu J$ is

In the Wheatstone's network given, \(P = 10\,\Omega , Q = 20\,\Omega , R = 15 \,\Omega , S = 30 \,\Omega\), the current passing through the battery (of negligible internal resistance) is

The potential of a large liquid drop when eight liquid drops are combined is 20 V. Then the potential of each single drop was

In hydrogen a atom, an electron is revolving in the orbit of radius $0.53\,�$ with $6.6 \times 10^{15}$ radiations/s. Magnetic field produced at the centre of the orbit is

In photoelectric emission process from a metal of work function $1.8 \,eV,$ the kinetic energy of most energetic electrons is $0.5 \,eV$. The corresponding stopping potential is

In the figure shown, the magnetic field induction as the point $O$ will be

A direct $X$ -ray photograph of the intenstines is not generally taken by radiologists because

The kinetic energy of an electron get tripled then the de-Broglie wavelength associated with it changes by a factor

A parallel plate capacitor has capacitance $C$. If it is equally filled the parallel layers of materials of dielectric constant $K_1$ and $K_2$ its capacity becomes $C_1$. The ratio of $C_1 $ and $C$ is

In the given circuit, the AC source has ? = 100 rad/s. Considering the inductor and capacitor to be ideal, the correct choice(s) is(are)

A uniform thin bar of mass $6m$ and length $12L$ is bent to make a regular hexagon. Its moment of inertia about an axis passing through the centre of mass and perpendicular to the plane of hexagon is

A steel wire can sustain $100\, kg$ weight without breaking. If the wire is cut into two equal parts, each part can sustain a weight of

Which of the following is the correct Kirchhoff's loop rule?

This question has Statement 1 and Statement 2. Of the four choices given after the Statements, choose the one that best describes the two Statements. If you push on a cart being pulled by a horse so that it does not move, the cart pushes you back with an equal and opposite force. The cart does not move because the force described in statement 1 cancel each other.

Two sources of sound placed close to each other, are emitting progressive waves given by $y _{1}=4 \sin 600\, \pi t$ and $y _{2}=5 \sin 608\, \pi t :$ An observer located near these two sources of sound will hear

The motion of a particle along a straight line is described by equation $ x = 8 + 12t - t^3 $ where $x$ is in metre and $t$ in second. The retardation of the particle when its velocity becomes zero is

The instantaneous values of alternating current and voltages in a circuit are given as $i=\frac{1}{\sqrt2}\sin(100\pi t)$ ampere $e=\frac{1}{\sqrt2}\sin(100\pi t+\frac{\pi}{3})$ Volt . The average power in watts consumed in the circuit is