List of top Physics Questions

Two pith balls carrying equal charges are suspended from a common point by strings of equal length, the equilibrium separation between them is 7. Now the strings are rigidly clamped at half the height. The equilibrium separation between the balls now become

A disc is performing pure rolling on a smooth stationary surface with constant angular velocity as shown in figure. At any instant, for the lower most point of the disc -

A gas is taken through the cycle A⇢B⇢C⇢A ,as shown. What is the net work done by the gas?

The condition under which a microwave oven heats up a food item containing water molecules most efficiently is

A body of mass w taken from the earth's surface to the height equal to twice the radius (R) of the earth. The change in potential energy of body will be

For a normal eye, the cornea of eye provides a converging power of 40 D and the least converging power of the eye lens behind the comes is 20 D. Using this information, the distance between the retina and the comea-eye lens can be estimated to be

In Young's double slit experiment, the slits are 2 mm apart and are illuminated by photons of two wavelengths, $λ_1$ =12000 Å and $λ_2$= 10000 Å. At what minimum distance from the common central bright fringe on the screen 2 m from the slit will a bright fringe from one interference patter coincide with a bright fringe from the other?

In an experiment four quantities a, b, c and d are measured with percentage error 1%, 2%, 3% and 4% respectively. Quantity P is calculated as follows: P= $\frac{a^3 b^2}{cd}$ % error in P is

Two identical capacitors, have the same capacitance $C$. One of them is charged to potential $V_{1}$ and the other to $V_{2}$. The negative ends of the capacitors are connected together. When the positive ends are also connected, the decrease in energy of the combined system is

The velocity and acceleration vectors of a particle undergoing circular motion are $\vec{ v }=2 \hat{ m } / s$ and $\vec{ a }=2 \hat{1}+4 \hat{ j } m / s ^{2}$ respectively at an instant of time. The radius of the circle is

A ball whose density is $0.4\times 10^3 kg/m^3$ falls into water from a height of $9\, cm$. To what depth does the ball sink ?

Two coaxial solenoids are made by winding thin insulated wire over a pipe of cross-sectional area $A=10\, cm ^{2}$ and length $=20\, cm$. If one of the solenoid has $300$ turns and the other $400$ turns, their mutual inductance is $\left(\mu_{0}=4 \pi \times^{-7} Tm A^{-1}\right)$

Seven resistance are connected between points $A$ and $B$ as shown in adjoining figure. The equivalent resistance between $A$ and $B$ is

A network of resistances, cell and capacitor $C( = 2 \,\mu F)$ is shown in adjoining figure. In steady state condition, the charge on $2 \,\mu F $capacitor is $Q$, while $R$ is unknown resistance. Values of $Q$ and $R$ are respectively

A body of mass $2 \,kg$ moving with velocity of $6\, m/s $ strikes in elastically with another body of same mass mass at rest. The amount of heat evolved during collision is

If a current $I$ is flowing in a loop of radius $r$ as shown in adjoining figure, then the magnetic field induction at the centre $O$ will be

The time dependence of a physical quantity $P$ is given by $P=P_{0} e \alpha P\left(-\alpha t^{2}\right)$ where $\alpha $ is a constant and $t$ is time. The constant $\alpha $

A lead shot of $1 \,mm$ diameter falls through a long column of glycerine. The variation of the velocity with distance covered (s) is correctly represented by

To get an $OR$ gate from a $NAND$ gate, we need

If the work done in turning a magnet of magnetic moment $M$ by an angle of 90$^{\circ}$ from the magnetic meridian is $n$ times the corresponding work done to turn it through an angle of 60$^{\circ}$, then the value of $n$ is

An element with atomic number $Z = 11$ emits $K_{\alpha} -$ X-ray of wavelength $\lambda$. The atomic number which emits $K_{\alpha} - $ $X$-ray of wavelength 4$\lambda$ is

Mobilities of electrons and holes in a sample of intrinsic germanium at room temperature are $0.36\,m^2V^{-1}s^{-1}$ and $0.17\,m^2V^{-1}s^{-1}$. The electron and hole densities are each equal to $2.5 \times 10^{19} m^3$. The electrical conductivity of germanium is

If a gas mixture contains 2 moles of $O_2$ and $4$ moles of $Ar$ at temperature $T$, then what will be the total energy of the system (neglecting all vibrational modes)

A students plots a graph between inverse of magnification 1/$m$ produced by a convex thin lens and the object distance $u$ as shown in figure. What was the focal length of the lens used?

Two balls of equal masses are thrown upwards along the same vertical direction at an interval of $2\, s$, with the same initial velocity of $39.2 \,m/s$. The two balls will collide at a height of