List of top Physics Questions

Masses of three wires of copper are in the ratio of $1 : 3 : 5$ and their lengths are in the ratio of $5 : 3 : 1$. The ratio of their electrical resistances is

In the circuit shown below, the current in the $1\Omega$ resistor is

A particle moves in a straight line with a constant acceleration. It changes its velocity from $10 ms^{-1}$ to $20ms^{-1}$ while passing through a distance 135 m in t second. The value of t is

Two bodies M and N of equal masses are suspended from two separate massless springs of spring constants kx and k2 respectively. If the two bodies oscillate vertically such that their maximum velocities are equal, the ratio of the one amplitude of vibration of M to that of N is

A freshly prepared radioactive source of half-life 2 h emits radiation of intensity which is 64 times the permissible safe level. The minimum time after which it would be possible to work safely with this source is

The velocity of sound in any gas depends upon

Two coherent monochromatic light beams of intensities I and 4I are superposed. The maximum and minimum possible intensities in the resulting beam are

The threshold frequency for photoelectric effect on sodium corresponds to a wavelength of $5000\, \mathring{A}.$ Its work function is

The energy of a photon of wavelength $?$ is

If $C$ and $R$ denote capacitance and resistance, the dimensional formula of $CR$ is

A boat which has a speed of $5\, km/h$ in still water crosses a river of width $1\, km$ along the shortest possible path in $15\, min$. The velocity of the river water in $km/h$ is

If one mole of a monoatomic gas ($\gamma$ = 5/ 3) is mixed with one mole of a diatomic gas ($\gamma$ = 7 / 5), the value of $\gamma$ for the mixture is

A cylinder of radius R made of a material of thermal conductivity $K_1$, is surrounded by a cylindrical shell of inner radius R and outer radius 2R made of a material of thermal conductivity K$_2$. The two ends of the combined system are maintained at two different temperatures. There is no loss of heat across the cylindrical surface and the system is in steady state. The effective thermal conductivity of the system is

A satellite $S$ is moving in an elliptical orbit around the earth. The mass of the satellite is very small compared to the mass of the earth. Then,

Let $I$ be the moment of inertia of a uniform square plate about an axis $AB$ that passes through its centre and is parallel to two of its sides. $CD$ is a line in the plane of the plate that passes through the centre of the plate and makes an angle $\theta$ with $AB$. The moment of inertia of the plate about the axis $CD$ is then equal to

The coefficient of restitution $e$, for a perfectly elastic collision is

A particle executes simple harmonic motion with a frequency f. The frequency with which its kinetic energy oscillates is

During a negative beta decay

A tube closed at one end containing air produces fundamental note of frequency $512\, Hz$. If the tube is open at both the ends, the fundamental frequency will be

A reference frame attached to the earth

Two thin long parallel wires separated by a distance b are carrying a current i ampere each. The magnitude of the force per unit length exerted by one wire on the other is

A simple pendulum of length L and mass (bob) M is oscillating in a plane about a vertical line between angular limits- $\phi$ and $+\phi$ For an angular displacement $\theta(| \theta |< \phi)$, the tension in the string and the velocity of the bob are T and v respectively. The following relations hold good under the above conditions

A proton moving with a constant velocity passes through a region of space without any change in its velocity. If E and B represent the electric and magnetic fields respectively. Then, this region of space may have

The X-ray beam coming from an X-ray tube will be

70 cal of heat are required to raise the temperature of2 moles of an ideal diatomic gas at constant pressure from 30$^{\circ}$C to 35$^{\circ}$C. The amount of heat required (in calorie) to raise the temperature of the same gas through the same range (30$^{\circ}$C to 35$^{\circ}$C) at constant volume is