List of top Physics Questions

The peak voltage in the output of a half-wave diode rectifier fed with a sinusoidal signal without a filter is 10V. The d. c. component of the output voltage is

In semiconductors at a room temperature

A stone is tied to a string of length 'l' and is whirled in a vertical circle with the other end of the string as the center. At a certain instant of time, the stone is at its lowest position and has a speed of 'u'. The magnitude of the change in velocity as it reaches a position where the string is horizontal (g being acceleration due to gravity) is

The refractive index of the material of a prism is 2 and its refracting angle is 30º. One of the refracting surfaces of the prism is made a mirror inwards. A beam of monochromatic light entering the prism from the other face will retrace its path after reflection form the mirrored surface if its angle of incidence on the prism is

A beam of light composed of red and green rays is incident obliquely at a point on the face of a rectangular glass slab. When coming out on the opposite parallel face, the red and green rays emerge from

The density of the newly discovered planet is twice that of earth. The acceleration due to gravity at the surface of the planet is equal to that at the surface of the earth. If the radius of the earth is R, the radius of the planet would be

A car is moving towards a high cliff. The car driver sounds a horn of the frequency 'f'. The reflected sound heard by the driver has a frequency of 2f. If 'v' is the velocity of sound then the velocity of the car, in the same velocity\ units, will be

Which one of the following statements is true for the speed 'v' and the acceleration 'a' of a particle executing simple harmonic motion

The unit of permittivity of free space ε₀ is

Angular velocity of minute hand of a clock is

In the relation $ y=a\,\,\cos \left( \omega t-kx \right) $ ,the dimensional formula for $k$ is :

The spring extends by $x$ on loading, then energy stored by the spring is : (if $T$ is the tension in spring and $k$ is spring constant)

The rotational kinetic energy of a body is $ {{K}_{rot}} $ and its moment of inertia is $ I $ . The angular momentum of body is:

An electron moving with a speed u along the positive x-axis at y = 0 enters a region of uniform magnetic field $B=-B_0 k$ which exists to the right of v-axis. The electron exits from the region after sometime with the speed v at coordinate y, then

Carbon dating is best suited for determining the age of fossils if their age in years is of the order of

The dimension of light year is :

When a resistance of $\alpha\, \Omega$ is connected at the ends of a battery, its potential difference decreases from $40\, V$ to $30\, V$. The internal resistance of the battery is

For the post office box arrangement to determine the value of unknown resistance, the unknown resistance should be connected between

A galvanometer gives full scale deflection with $0.2\, A$ in a coil shown in the figure. The resistance of its coil is $ 10\,\Omega $ . How much shunt resistance is required to convert it into an ammeter to read current upto $1.8\, A$ ?

The thermo emf of a thermocouple varies with the temperature $?$ of the hot junction as $E = a \,? + b?^2$ in volts where the ratio $a/b$ is $700^{\circ}C$. If the cold junction is kept at $0^{\circ}C$, then the neutral temperature is

An electric current is passed through a circuit containing two wires of the same material, connected in parallel. If the length and radii of the wires are in the ratio of $4/3$ and $2/3$, then the ratio of the currents passing through the wire will be

A larger dry cell has higher emf. The emf of a dry cell is proportional to its size.

Current provided by a battery is maximum when: