List of top Physics Questions

A long string is stretched by $2\, cm$ and the potential energy is $V$. If the spring is stretched by $10\, cm$, its potential energy will be
In the equation $PV^\gamma$ = constant, the value of $\gamma$ is unity. Then the process is
Which of the following is best nuclear fuel
The upper end of a wire of diameter $12\,mm$ and length $1\,m$ is clamped and its other end is twisted through an angle of $30^{\circ}$. The angle of shear is
A spring is compressed between two toy carts of mass $m_1$ and $m_2$. When the toy carts are released, the springs exert equal and opposite average forces for the same time on each toy cart. If $V_1$ and $V_2$ are the velocities of the toy carts and there is no friction between the toy carts and the ground, then :
One kilogram of ice at $0^{\circ} C$ is mixed with one kilogram of water at $80^{\circ} C$. The final temperature of the mixture is (Take specific heat of water $=4200\, kJ / kg -{ }^{\circ} C$, Latent heat of ice $=336\, kJ / kg$ )
An ideal refrigerator has a freezer at a temperature of $-13^{\circ} C$. The coefficient of performance of the engine is $5$. The temperature of the air (to which heat is rejected) is
Which of the following does not depict the correct link between technology and physics?
Two planets $A$ and $B$ have the same material density. If the radius of $A$ is twice that of $B$, then the ratio of the escape velocity $V_{A} / V_{B}$ is
Two circular plates of radius $5\, cm$ each, have a $0.01\, mm$ thick water film between them. Then what will be the force required to separate these plate (S.T. of water = $73$ dyne/cm) ?
Suppose the gravitational force varies inversely as the nth power of distance. Then the time period of a planet in circular orbit of radius $R$ around the sun will be proportional to
The power dissipated in the circuit shown in the figure is $30$ Watts. The value of $R$ is
A point charge $+q$ is placed at the centre of a cube of side $L$. The electric flux emerging from the cube is
An object moving at a speed of $ 5\,m/s $ towards a concave mirror of focal length $ f = 1\, m $ is at a distance of $ 9\, m $ . The average speed of the image is
A proton of mass $ 1.67 \times 10^{-27}\, kg$ enters a uniform magnetic field $1\, T$ of at point A shown in figure with a speed of $10^7\, ms^{-1}$ The magnetic field is directed normal to the plane of paper downwards. The proton emerges out of the magnetic field at point $C$, then the distance $AC$ and the value of angle $\theta $ will respectively be
The collector plate in an experiment on photoelectric effect is kept vertically above the emitter plate. Light source is put on and a saturation photo-current is recorded. An electric field is switched on which has a vertically downward direction, then
In Meter bridge or Wheatstone bridge for measurement of resistance, the known and the unknown resistances are interchanged. The error so removed is
Which of the following rays is emitted by a human body?
Zener diode is used for
A potential difference of $2\, V$ is applied between the opposite faces of a $Ge$ crystal plate of area $1\, cm ^{2}$ and thickness $0.5 mm$. If the concentration of electrons in $Ge$ is $2 \times 10^{19} / m ^{2}$ and mobilities of electrons and holes are $0.36\, m ^{2} V ^{-1} s ^{-1}$ and $0.14\, m ^{2} V ^{-1} s ^{-1}$ respectively, then the current flowing through the plate will be
A straight wire carrying current i is turned into a circular loop. If the magnitude of magnetic moment associated with it in MKS unit is M, the length of wire will be
An arc of radius $r$ carries charge. The linear density of charge is $\lambda$ and the arc subtends an angle $\frac{\pi}{3}$ at the centre. What is electric potential at the centre?
Sinusoidal carrier voltage of frequency $1.5\, MHz$ and amplitude $50\, V$ is amplitude modulated by sinusoidal voltage of frequency $10\, kHz$ producing $50 \%$ modulation. The lower and upper side-band frequencies in $kHz$ are
In the hydrogen atom, the electron is making $6.6 \times 10^{15}$ rps. If the radius of orbit is $0.53 \times 10^{-10}$ m, then magnetic field produced at the centre of the orbit is
The ratio of the amounts of heat developed in the four arms of a balance Wheatstone bridge, when the arms have resistances $P = 100\, \Omega,\,Q = 10\, \Omega,\, R = 300\, \Omega$ and $S = 30\, \Omega$ respectively is