List of top Physics Questions

A particle of mass $m$ is moved from the surface of the earth to a height $h$. The work done by an external agency to do this is (1) $m g h$ for $h < < R$ (3) $\frac{1}{2} m g h$ for $h=R$ (2) $m g h$ for all $h$ (4) $-\frac{1}{2} m g h$ for $h=R$
If the energy of a 100 $ \pi F $ capacitor charged to 6 kV could all be used to lift a 50 kg mass, hat would be the greatest vertical height through which mass could be raised?
Out of the following gases under similar condition of temperature and pressure, the velocity of sound will be maximum in
If the resistivity of pure silicon is $3000 \, \Omega m$ and the mobilities of electrons and holes are $0.12 \, m^{2}V^{- 1}s^{- 1}$ and $0.045 \, m^{2}V^{- 1}s^{- 1}$ respectively, then what will be the resistivity of a specimen of silicon when $10^{19}$ atoms of phosphorous are added per cubic metre?
An aluminium rod and a copper rod are taken such that their lengths are same and their resistances are also same. The specific, resistance of copper is half that of aluminium, but its density is three times that of aluminium. The ratio of the mass of aluminium rod and that of copper rod will be
Two soap bubbles have radii in the ratio of 2:1. What is the ratio of excess pressures inside them?
Each of the two point charges are doubled and their distance is halved. Force of interaction becomes n times, where n is
A balloon is filled with hydrogen. For sound waves, this balloon behaves like
A common hydrometer reads specific gravity of liquids. Compared to the 1.6 mark of the stem the mark 1.5 will be
Which of the following is different from others?
Two pendulums have time periods T and 5T/4. They starts SHM at the same time from the mean position. What will be the phase difference between them after the bigger pendulum completed one oscillation ?
A beam of metal supported at the two ends is loaded at tlie centre. The depression at the centre is proportional to
Given that the displacement of an oscillating particle is given by $ y=Asin(B~+Ct+D) $ . The dimensional formula for (ABCD) is
Assume that the nuclear binding energy per nucleon ( $B/A$ ) versus mass number ( $A$ ) is as shown in the figure. Use this plot to choose the correct choice given below.
Angular momentum of hydrogen atom: angular momentum of $Li^{++}$ ion is
The energy gap between the valence band and the conduction band for a material is 6 eV. The material is
An isolated particle of mass $m$ is moving in a horizontal plane$ (x-y)$ along the $x$-axis, at a certain height above the ground. It suddenly explodes into two fragments of masses $m/4$ and $3m/4$ . An instant later, the smaller fragment is at $y = +15 \,cm$. The larger fragment at this instant is at
An ideal fluid flows through a pipe of circular cross-section made of two sections with diameters $2.5\, cm$ and $3.75\, cm$. The ratio of the velocities in the two pipes is
An equilateral triangular loop of wire of side $2l$ carries a current $I$. The magnetic field produced at the centre of the loop is
A uniform solid right circular cone of base radius $r$ is joined to a uniform solid hemisphere of radius $r$ and of the same density, so as to have a common face. The centre of mass of the composite solid lies on the common face. The height of the cone is
A uniform rod of mass $m$, length $L$, area of cross-section $A$ and Young's modulus $Y$ hangs from a rigid support. Its elongation due to its own weight will be
An $RL$ circuit in which $R = 5\,\Omega$ and $L = 4\,H$ is connected to a $22\, V$ battery at $t = 0$. For this circuit at what rate the energy is being stored in the inductor when the current in circuit is $1 \,A$ ?
A disc is placed on a surface of pond which has refractive index $5/3$. A source of light is placed $4\,m$ below the surface of liquid. The minimum radius of disc needed so that light is not coming out is
At time $t = 0$, activity of radioactive substance is $1600 \,Bq$, at $t = 8 \,s$ activity falls to $100 \,Bq$. The activity at $t = 2\, s$ is
An echo repeats four syllables. The distance of the reflecting surface, if it takes one-fifth of a second to pronounce or hear one syllable distinctly is (Velocity of sound $= 340\,ms^{-1}$)