List of top Physics Questions

In normal adjustment, for a refracting telescope, the distance between the objective and eyepiece lens is 1.00 m. If the magnifying power of the telescope is 19, find the focal length of the objective and the eyepiece lens.

An air bubble is trapped at point B (CB = 20 cm) in a glass sphere of radius 40 cm and refractive index 1.5 as shown in the figure. Find the nature and position of the image of the bubble as seen by an observer at point P. 

Two electric heaters have power ratings \( P_1 \) and \( P_2 \), at voltage \( V \). They are connected in series to a DC source of voltage \( V \). Find the power consumed by the combination. Will they consume the same power if connected in parallel across the same source?

A ray of light is incident normally on one face of an equilateral glass prism of refractive index \( P \). When the prism is completely immersed in a transparent medium, it is observed that the emergent ray just grazes the adjacent face. Find the refractive index of the medium.

A proton and an \( \alpha \)-particle are accelerated through different potentials \( V_1 \) and \( V_2 \) respectively so that they have the same de Broglie wavelengths. Find \( \frac{V_1}{V_2} \).

Draw the circuit diagram of a p-n junction diode in
(i) forward biasing and
(ii) reverse biasing.
Also, draw its I-V characteristics in the two cases.

Assertion (A): In interference and diffraction of light, light energy reduces in one region producing a dark fringe. It increases in another region and produces a bright fringe.
Reason (R): This happens because energy is not conserved in the phenomena of interference and diffraction.

Assertion (A): When electrons drift in a conductor, it does not mean that all free electrons in the conductor are moving in the same direction.
Reason (R): The drift velocity is superposed over large random velocities of electrons.

Assertion (A): The temperature coefficient of resistance is positive for metals and negative for p-type semiconductors.
Reason (R): The charge carriers in metals are negatively charged, whereas the majority charge carriers in p-type semiconductors are positively charged.

Assertion (A): Electrons are ejected from the surface of zinc when it is irradiated by yellow light.
Reason (R): Energy associated with a photon of yellow light is more than the work function of zinc.

In the Balmer series of the hydrogen atom, as the wavelength of spectral lines decreases, they appear:

The phase difference between electric field \( \vec{E} \) and magnetic field \( \vec{B} \) in an electromagnetic wave propagating along the z-axis is:

Figure shows the variation of inductive reactance \( X_L \) of two ideal inductors of inductance \( L_1 \) and \( L_2 \) with angular frequency \( \omega \). The value of \( \frac{L_1}{L_2} \) is: 

A circular loop A of radius \( R \) carries a current \( I \). Another circular loop B of radius \( r = \frac{R}{20} \) is placed concentrically in the plane of A. The magnetic flux linked with loop B is proportional to:

A galvanometer of resistance 100 \( \Omega \) is converted into an ammeter of range (0 – 1 A) using a resistance of 0.1 \( \Omega \). The ammeter will show full-scale deflection for a current of about:

The magnetic susceptibility for a diamagnetic material is:

A straight wire is kept horizontally along the east-west direction. If a steady current flows in the wire from east to west, the magnetic field at a point above the wire will point towards:

The radius \( r_n \) of the \( n^{th} \) orbit in the Bohr model of the hydrogen atom varies with \( n \) as:

The quantum nature of light explains the observations on the photoelectric effect as:

Two identical small conducting balls \( B_1 \) and \( B_2 \) are given \(-7\) \(\mu C\) and \(+4\) \(\mu C\) charges respectively. They are brought in contact with a third identical ball \( B_3 \) and then separated. If the final charge on each ball is \(-2\) \(\mu C\), the initial charge on \( B_3 \) was:

Two charges \(+q\) each are kept \(2a\) distance apart. A third charge \(-2q\) is placed midway between them. The potential energy of the system is:

"The height from Earth's surface at which acceleration due to gravity becomes \( g/4 \), where \( g \) is acceleration due to gravity on the surface of Earth and \( R \) is the radius of Earth?"

"Water is flowing through a horizontal pipe in stream line flow at the narrowest part of the pipe?"

Two monkeys of mass 10 kg and 8 kg are moving along a vertical light rope. The former is climbing up with an acceleration of \( 2 \, \text{m/s}^2 \), while the latter is coming down with a uniform velocity. Find the tension in the rope at the fixed support.

An e.m.f of 5 volts is produced by a self-inductance when the current changes at a steady rate from 3A to 2A in 1 millisecond. The value of self-inductance is: