List of top Physics Questions

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:
A body is thrown vertically up with certain initial velocity. The potential and kinetic energies of the body are equal at a point P in its path. If the same body is thrown with double the velocity upwards, the ratio of potential and kinetic energies of the body when it crosses the same point, is
A table tennis ball which has been covered with a conducting paint is suspended by a silk thread so that it hangs between two metal plates. One plate is earthed. When the other plate is connected to a high voltage generator, the ball
Millikan's oil-drop experiment established that
The ground state energy of hydrogen atom is -13.6 eV. When its electron is in the first excited state, its excitation energy is
Two nuclei have their mass numbers in the ratio of $ 1:3 $ . The ratio of their nuclear densities would be
The radius of curvature of the convex face of a planoconvex lens is $ 15 \,cm $ and the refractive index of the material is $ 1.4 $ . Then the power of the lens in dioptre is
The ratio of the nuclear radii of elements with mass numbers $216$ and $125$ is
The moment of inertia of a thin circular disc about an axis passing through its center and perpendicular to its plane is $1$. Then, the moment of inertia of the disc about an axis parallel to its diameter and touching the edge of the rim is
The coefficient of thermal conductivity of copper is $9$ times that of steel. In the composite cylindrical bar shown in the figure, what will be the temperature at the junction of copper and steel ?
A fish in water (refractive index $n$) looks at a bird vertically above in the air. If $y$ is the height of the bird and $x$ is the depth of the fish from the surface, then the distance of the bird as estimated by the fish is