List of top Physics Questions

Numerical aperture of an oil immersion objective using oil of R.I. 1.5 is 0.75. Then, its numerical aperture, when kept in air is
A mirror produces a magnified erect image of an object. The nature of the mirror is
Time of exposure for a photographic print is 10 s, when a lamp of 50 cd is placed at 1 m from it. Then another lamp of luminous intensity I is used, and is kept at 2 m from it. If the time of exposure now is 20 sec, the value of I is (cd)
A quanity of heat required to change the unit mass of a solid substance, from solid state to liquid state, while the temperature remains constant, is known as
The waves in which the particles of the medium vibrate in a direction perpendicular to the direction of wave motion is known as
If the kinetic energy of a body becomes four times of its initial value, then new momentum will
The dimensions of angular velocity, is
If the equation for the displacement of a particle moving on a circular path is given by $(\theta)=$ $2 t^{3}+0.5$ where $\theta$ is in radians and $t$ in seconds, then the angular velocity of the particleat $t = 2\, sec$, is
A bullet is fired from a rifle. If the rifle recoils freely, then the kinetic energy of the rifle, is
A metal beam having coefficient of linear expansion $ \alpha $ Youngs modulus $ Y $ , area of across section a and length L, is clamped at both ends. After cooling by $ t{}^\circ C, $ the force exerted in the clamp is
A vessel contains a mixture of one mole of oxygen and two moles of nitrogen at 300 K. The ratio of the average rotational kinetic energy per O$_2$ molecule to per N$_2$ molecule is
A string of length 0.4 m and mass $10^{-2} kg$ is tightly clamped at its ends. The tensior in the string is 1.6 N. Identical wave pulses are produced at one end at equal intervals of time $\Delta t.$ The minimum value of $\Delta t.$ which allows constructive interference between successive pulses, is
A black body is at a temperature of 2880 K. The energy of radiation emitted by this body with wavelength between 499 nm and 500 nm is$U_1$, between 999 nm and 1000 nm is $U_2$ and between 1499 nm and 1500 nm is $U_3$. The Wien constant, b = 2.88 $\times 10^6$ nm-K. Then,
The torque $\tau$ on a body about a given point is found to be equal to A x L, where A is a constant vector and L is the angular momentum of the body about that point. From this it follows that
The linear momentum p of a body varies with time and it is given by equation $ p=x+y{{t}^{2}} $ where $ x $ and $ y $ are constants. The net force acting on the body for a one dimensional motion is :
In a p-n-p transistor working as common base amplifier, current gain is 0.96 and emitter current is 7.2 mA. Then base current will be:
The number of degrees of freedom for each atom of a monatomic gas is
The magnifying power of a simple microscope M is given by
A stone of mass 1 kg tied to the end of a string of length 1 m, is whirled in a horizontal circle, with a uniform angular velocity 2 radian/sec. The tension of the string is (N)
A light body A and a heavy body B have equal linear momentum. Then the K.E. of the body A
A mass of $1 \,kg$ is suspended by means of a thread. The system is (i) lifted up with an acceleration of $4.9 \,m$ $s^{-2}$ (ii) lowered with an acceleration of $4.9 \,m$ $s^{-2}$ . The ratio of tension in the first and second case is
A simple harmonic oscillator oscillates with an amplitude A. At what displacement the kinetic energy and potential energies are equal:
One standard atomic mass unit is:
If 11 identical resistances each of resistance r ohm are in parallel, the equivalent resistance of the combination would be:
If z is the atomic number then radius of g first Bohr orbit is proportional to :