List of top Physics Questions

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
There are a $25\, W -220\, V$ bulb and a $100\, W-220\, V$ line. Which electric bulb will glow more brightly?
A neutral water molecule $(H_2O)$ in its vapour state has an electric dipole moment of magnitude $6.4 \times 10^{-30} C-m$ . How far apart are the molecules centres of positive and negative charges?
A small coil is introduced between the poles of an electromagnet so that its axis coincides with the magnetic field direction. The number of turns is n and the cross-sectional area of the coil is $A$. When the coil turns through $180^{\circ}$ about its diameter, the charge flowing through the coil is $Q$. The total resistance of the circuit is $R$. What is the magnitude of the magnetic induction?
Two light sources are said to be coherent if they are obtained from
Magnetic field at the centre of a circular loop of area $A$ is $B$. The magnetic moment of the loop will be
Zener diode is used for
Figure shows a straight wire length $l$ carrying current $i$. The magnitude of magnetic field produced by the current at point $P$ is.