List of top Physics Questions

The magnetic susceptibility of iron is 5499 . The relative permeability of iron will be
A wire of length L , diameter ' d ' density of material ' e ' is under tension ' T ', having fundamental frequency of vibration $\text{n}_\text{A}$. Another wire of length 2 L , tension 2 T , density 2 e and diameter 3 d has fundamental frequency of vibration $\text{n}_\text{B}$. The ratio $\text{n}_\text{B} : \text{n}_\text{A}$ is
' n ' small spherical drops of same size which are charged to ' $V$ ' volt each coalesce to form a single big drop. The potential of the big drop is
The length of the compound microscope is $15\text{ cm}$ . The magnifying power for relaxed eye is 25 . If the focal length of eye lens is $6\text{ cm}$ then the object distance for objective lens will be}
A particle oscillates in straight line simple harmonically with period 8 second and amplitude $4\sqrt{2}\text{ m}$. Particle starts from mean position. The ratio of the distance travelled by it in $1^{\text{st}}$ second of its motion to that in $2^{\text{nd}}$ second is $\left(\sin 45^\circ = 1/\sqrt{2}, \sin\frac{\pi}{2} = 1\right)$}
In a transistor (common emitter configuration) the ratio of power gain to voltage gain is ( $\alpha$ and $\beta$ are current ratios)
A water drop of $0.01\text{ cm}^3$ is squeezed between two glass plates and spreads in to area of $10\text{ cm}^2$ . If surface tension of water is $70\text{ dyne /cm}$ then the normal force required to separate glass plates from each other will be}
In Young's double slit experiment, for the $n$th dark fringe ($n = 1, 2, 3\dots$) the phase difference of the interfering waves in radian will be
A resistance of $200\Omega$ and an inductor of $\frac{1}{2\pi}\text{ H}$ are connected in series to a.c. voltage of $40\text{ V}$ and $100\text{ Hz}$ frequency. The phase angle between the voltage and current is
A long wire carrying a steady current is bent into a circle of single turn. The magnetic field at the centre of the coil is ' $\text{B}$ '. If it is bent into a circular loop of radius ' $\text{r}_1$ ' having ' $\text{n}$ ' turns, the magnetic field at the centre of the coil for same current is
Two spheres each of mass $M$ and radius $R$ are connected with a massless rod of length $4 R$ . The moment of inertia of the system about an axis passing through the centre of one of the spheres and perpendicular to the rod will be
A null point is obtained at $200\text{ cm}$ on potentiometer wire when cell in secondary circuit is shunted by $5\Omega$. When a resistance of $15\Omega$ is used for shunting, null point moves to $300\text{ cm}$ . The internal resistance of the cell is
Two planar concentric rings of metal wire having radii $\text{r}_1$ and $\text{r}_2$ ( $\text{r}_1 > \text{r}_2$ ) are placed in air. The current $\text{I}$ is flowing through the coil of larger radius. The mutual inductance between the coils is given by ( $\mu_0 =$ permeability of free space)}
An inclined plane makes an angle $30^\circ$ with the horizontal. A solid sphere rolling down an inclined plane from rest without slipping has linear acceleration ( $\text{g} =$ acceleration due gravity) ( $\sin 30^\circ = 0.5$ )
Two pipes of lengths $\text{L}_1$ and $\text{L}_2$, open at both ends are joined in series. If ' $f_1$ ' and ' $f_2$ ' are the fundamental frequencies of two pipes, then the fundamental frequency of series combination will be (neglect end correction)}
A conducting sphere of radius ' $\text{R}$ ' is given a charge ' $Q$ ' uniformly. The electric field and the electric potential at the centre of the sphere are respectively [ $\varepsilon_0 =$ permittivity of free space]}
The work done by a gas as it is taken in a cyclic process (shown in graph) is
The coefficient of mutual induction is $2\text{ H}$ and induced e.m.f. across secondary is $2\text{ kV}$ . Current in the primary is reduced from $6\text{ A}$ to $3\text{ A}$ . The time required for the change of current is
A liquid drop having surface energy $E$ is spread into 729 droplets of same size. The final surface energy of the droplets is
A diatomic gas $\left(\gamma = \frac{7}{5}\right)$ is compressed adiabatically to volume $\frac{\text{V}_0}{32}$ , where $\text{V}_0$ is its initial volume. The initial temperature of the gas is $\text{T}_\text{i}$ in kelvin and the final temperature is $\text{x}\text{T}_\text{i}$ in kelvin. The value of $x$ is
The surface energy of a liquid drop is ' $V$ '. It is sprayed into 1000 equal droplets. The surface energy of all the droplets is
A hollow cylinder has a charge of ' $q$ ' $C$ within it. If $\phi$ is the electric flux associated with the curved surface B, the flux linked with the plane surface A will be
The average force applied on the walls of a closed container depends as $\text{T}^\text{x}$ where T is the temperature of an ideal gas. The value of $x$ is
Three point charges $+Q, +2Q$ and $q$ are placed at the vertices of an equilateral triangle. The value of charge $q$ in terms of $Q$, so that electrical potential energy of the system is zero, is given by
When an n-p-n junction transistor is used as an amplifier in common emitter mode,