List of top Physics Questions

A current of 3 amp. flows through the $2\, \Omega$ resistor shown in the circuit. The power dissipated in the $5\, \Omega$ resistor is

In gamma ray emission from a nucleus

A simple pendulum is suspended from the ceiling of a lift. When the lift is at rest its time period is $T$. With what acceleration should the lift be accelerated upwards in order to reduce its period to $T/2$ ? (g is acceleration due to gravity).

The magnetic field at the centre of a circular current carrying conductor of radius $r$ is $B_c$. The magnetic field on its axis at a distance $r$ from the centre is $B_a$. The value of $B_c : B_a$ will be

The equivalent resistance between the points $A$ and $B$ will be (each resistance is 15 $\Omega$)

The masses of two radioactive substances are same and their half lives are $1$ year and $2$ years respectively. The ratio of their activities after 6 years will be

The communication using optical fibers is based on the principle of

$K_{\alpha} $ and $K_{\beta} x-$ rays are emitted when there is a transition of electron between the levels

In the circuit shown above, an input of \(1\,V\) is fed into the inverting input of an ideal Op-amp \(A\). The output signal \(V_{\text{out}}\) will be

In Colpitt oscillator the feedback network consists of

A small conducting sphere of radius $r$ is lying concentrically inside a bigger hollow conducting sphere of radius $R$. The bigger and smaller spheres are charged with $Q$ and $q (Q > q)$ and are insulated from each other. The potential difference between the spheres will be

A ray of light enters from a rarer to a denser medium. The angle of incidence is $i$. Then the reflected and refracted rays are mutually perpendicular to each other. The critical angle for the pair of media is

$_{92}U^{235}$ undergoes successive disintegrations with the end product of $_{82}Pb^{203}$.The number of $\alpha$ and $\beta$ particles emitted are

A body of mass $4\, kg$ is accelerated upon by a constant force, travels a distance of $5\,m$ in the first second and a distance of $2\,m$ in the third second. The force acting on the body is

A mass of $10\,kg$ is suspended from a spring balance. It is pulled aside by a horizontal string so that it makes an angle of $60^\circ$ with the vertical. The new reading of the balance is

Two identical metal spheres charged with $+12 \mu F$ and $-8 \mu F$ are kept at certain distance in air. They are brought into contact and then kept at the same distance. The ratio of the magnitudes of electrostatic forces between them before and after contact is

Figure shows a mixture of blue, green and red coloured rays incident normally on a right angled prism. The critical angles of the material of the prism for red, green and blue are $46^\circ$, $44^\circ$ and $43^\circ$ respectively. The arrangement will separate

A body of mass $3 \,kg$ is under a constant force which causes a displacement s in metre in it, given by the relation $s=\frac{1}{3}t^2$, where $t$ is in second. Work done by the force in $2 s$ is

A player caught a cricket ball of mass 150 g moving at a rate of 20 m/s. If the catching process is completed in 0.1s, the force of the blow exerted by the ball on the hand of the player is equal to :

The energy required to charge a parallel plate condenser of plate separation d and plate area of cross-section A such that the uniform electric field between the plates is E, is

The value of alternating emf $E$ in the given circuit will be

On bombarding $U^{235}$ by slow neutron, $200\, MeV$ energy is released. If the power output of atomic reactor is $1.6\, MW$, then the rate of fission will be

The equation of a simple harmonic wave is given by $y = 6\, Sin\, 2\pi(2t - 0.1x)$, where $x$ and $y$ are in $mm$ and $t$ is in seconds. The phase difference between two particles $2\, mm$ apart at any instant is

A particle located at x = 0 at time t - 0, starts moving along the positive x-direction with a velocity 'V' that varies as $v=\alpha\sqrt{x.}$ The displacement of the particle varies with time as:

A bomb of mass 16 kg at rest explodes into two pieces of masses 4 kg and 12 kg. The velocity of the 12 kg mass is 4 $ms^{-1}.$The kinetic energy of the other mass is: