List of top Physics Questions

A box is moved along a straight line by a machine delivering constant power. The distance moved by the body in time $t$ is proportional to
A solid conducting sphere having a charge Q is surrounded by an uncharged concentric conducting hollow spherical shell. Let the potential difference between the surface of the solid sphere and that of the outer surface of the hollow shell be V. If the shell is now given a change of - 3Q, the new potential difference between the same two surfaces is
A ray of light from a denser medium strikes a rarer medium at an angle of incidence i (see figure). The reflected and refracted rays make an angle of $90^\circ$ with each other. The angles of reflection and refraction are r and r'. The critical angle is
The equation; \(4\space _1^1H \rightarrow _4^2{He}^2+2e^-+26 MeV\)
The current i in the circuit (see figure) is
A hollow metal sphere of radius 5 cm is charged such that the potential on its surface is 10 V. The potential at the centre of the sphere is.
Beta rays emitted by a radioactive material are
An ideal monoatomic gas is taken round the cycle $ABCDA$ as shown in the P - V diagram (see figure). The work done during the cycle is
A thin circular ring of mass M and radius r is rotating about its axis with a constant angular velocity $\omega$. Two objects, each of mass m, are attached gently to the opposite ends of a diameter of the ring. The wheel now rotates with an angular velocity
A conducting circular loop of radius r carries a constant current i . It is placed in a uniform magnetic field $B_0$ such that $B_0$ is perpendicular to the plane of the loop. The magnetic force acting on the loop is
If elements with principal quantum number $n > 4$ were not allowed in nature, the number of possible elements would be
Consider the spectral line resulting from the transition $n=2\rightarrow n=1$ in the atoms and ions given below. The shortest wavelength is produced by
Two particles which are initially at rest, move towards each other under the action of their internal attraction. If their speeds are $v$ and $2v$ at any instant, then the speed of centre of mass of the system will be
A convex lens of focal length 40 cm is in contact with a concave lens of focal length 25 cm. The power of the combination is
The threshold wavelength for photoelectric emission from a material is $5200\mathring{A}$. Photoelectrons will be emitted when this material is illuminated with monochromatic radiation from a
In the Young's double slit experiment, the interference pattern is found to have an intensity ratio between the bright and dark fringes as 9, This implies that
In the arrangement shown in the figure, the ends P and Q of an unstretchable string move downwards with uniform speed U. Pulleys A and B are fixed. Mass M moves upwards with a speed
A particle is moving eastwards with a velocity of $5\, m / s$. In $10\, s$ the velocity changes to $5\, m / s$ northwards. The average acceleration in this time is
A glass prism of refractive index 1.5 is immersed in water (refractive index 4/3). A light beam incident normally on the face AB is totally reflected to reach the face BC if
The plate resistance of a triode is $3 \times 10^3 \Omega$ and its mutual conductance is $1.5 \times 10^{-3} A/V$. The amplification factor of the triode is
An alpha particle of energy $5 \,MeV$ is scattered through $180^\circ$ by a fixed uranium nucleus. The distance of closest approach is of the order of
The half-life of the radioactive radon is 3.8 days. The time, at the end of which 1/20th of the radon sample will remain undecayed, is (given $log_{10} e = 0.4343$)
In the circuit shown in figure the heat produced in the $5\Omega$ resistor due to the current flowing through it is 10 cal/s. The heat generated in the $4\Omega$ resistor is
Two copper balls, each weighing 10 g , are kept in air 10 cm apart. If one electron from every $10^6$ atoms is transferred from one ball to the other, the coulomb force between them is (atomic weight of copper is 63.5)
If a machine is lubricated with oil