List of top Physics Questions

Which of the following statement is true?
Consider a parallel plate capacitor of $10\,\mu F$ (micro-farad) with air filled in the gap between the plates. Now one-half of the space between the plates is filled with a dielectric of dielectric constant $4$, as shown in the figure. The capacity of the capacitor changes to
Permanent magnet has properties retentivity and coercivity respectively
A frictionless track $A B C D E$ ends in a circular loop of radius $R. A$ body slides down the track from point $A$ which is at a height $h = 5 \,cm$ . Maximum value of $R$ for the body to successfully complete the loop is
The angle for which maximum height and horizontal range are same for a projectile is
Figure shows four paths for a kicked football. Ignoring the effects of air on the flight, rank the paths according to initial horizontal velocity component, highest first
A tube of length $L$ is filled completely with an incompressible liquid of mass $M$ and closed at both the ends. The tube is then rotated in a horizontal plane about one of its ends with a uniform angular velocity $\omega.$ The force exerted by the liquid at the other end is
Which motion does not require force to maintain it?
A ball of mass $m$ elastically collides with a wall with velocity $v$, the $n$ change in its momentum is equal to
An engine pumps up $100\, kg$ of water through a height of $10 \,m$ in $5 \,s$ . Given that, the efficiency of engine is $60\%$ If $ g=10\,ms^{-2}$ the power of this engine is
Two particles of mass $m$ each are tied at the ends of a light string of length $2a$. The whole system is kept on a frictionless horizontal surface with the string held tight so that each mass is at a distance $a$ from the centre $P$ (as shown in the figure). 
Now, the mid-point of the string is pulled vertically upwards with a small but constant force $F$. As a result, the particles move towards each other on the surface. The magnitude of acceleration, when the separation between them becomes $2x $ is
A charged particle moves through a magnetic field in a direction perpendicular to it. Then the
Light year is used to measure
"Parsec" is the unit of
Two bodies, $A$ (of mass $1\, kg$) and $B$ (of mass $3 \,kg$) are dropped from heights of $16\, m$ and $25 \,m$, respectively. The ratio of the time taken by them to reach the ground is:-
Two balls are dropped to the ground from different heights. One ball is dropped $ 2\, s $ after the other but they both strike the ground at the same time. If the first ball takes $ 5\, s $ to reach the ground, then the difference in initial heights is $ (g=10m{{s}^{-2}}) $
Total internal reflection takes place
A transistor is operated in common emitter configuration at constant collector voltage $ {{V}_{C}}=1.5\,V $ such that a change in the base current from 100 $ \mu A $ to 150 $ \mu A $ produces a change in the collector current from 5 mA to 10 mA. The current gain ( $ \beta $ ) is
The total energy of an electron in the first excited state of hydrogen is about $- 3.4 \,eV$. Its kinetic energy in this state is
The surface temperature of the Sun which has maximum energy emission at $500 \,nm$ is $6000 \,K$. The temperature of a star which has maximum energy emission at $400\, nm$ will be
The resistance of an ammeter is $ 13 \Omega$ and its scale is graduated for a current upto $100$ amps. After an additional shunt has been connected to this ammeter it becomes possible to measure currents upto $750$ amperes by this meter. The value of shunt-resistance is
Select the true statement from the following. Nuclear force is
One end of a thermally insulated rod is kept at a temperature $T_1$ and the other at $T_2$. The rod is composed of two sections of lengths $\ell_{1}$ and $\ell_{2}$ and thermal conductivities $k_1$ and $k_2$ respectively. The temperature at the interface of the two sections is
Magnetic field produced due to a current carrying conductor is independent of
In a semiconductor electron concentration is $7 \times 10^{13} \,cm ^{-3}$ and hole concentration is $5 \times 10^{12} \,cm ^{-3}$. Then the semiconductor is