List of top Physics Questions

A parallel plate capacitor was made with two rectangular plates, each with a length of \( l = 3 \, {cm} \) and breadth of \( b = 1 \, {cm} \). The distance between the plates is \( d = 3 \, \mu{m} \). Out of the following, which are the ways to increase the capacitance by a factor of 10?
  • A. l = 30 cm, b = 1 cm, d = 1 μm
  • B. l = 3 cm, b = 1 cm, d = 30 μm
  • C. l = 6 cm, b = 5 cm, d = 3 μm
  • D. l = 1 cm, b = 1 cm, d = 10 μm
  • E. l = 5 cm, b = 2 cm, d = 1 μm
A satellite is launched into a circular orbit of radius \( R \) around the earth. A second satellite is launched into an orbit of radius \( 1.03R \). The time period of revolution of the second satellite is larger than the first one approximately by:

A point particle of charge \( Q \) is located at \( P \) along the axis of an electric dipole 1 at a distance \( r \) as shown in the figure. The point \( P \) is also on the equatorial plane of a second electric dipole 2 at a distance \( r \). The dipoles are made of opposite charge \( q \) separated by a distance \( 2a \). For the charge particle at \( P \) not to experience any net force, which of the following correctly describes the situation?


 

A 1 cm straight segment of a conductor carrying 1 A current in \( x \)-direction lies symmetrically at the origin of Cartesian coordinate system. The magnetic field due to this segment at point (1m, 1m, 0) is:
The above battery sends a current \( I_1 \) when \( R = R_1 \) and a current \( I_2 \) when \( R = R_2 \). Obtain the internal resistance of the battery in terms of \( I_1 \), \( I_2 \), \( R_1 \), and \( R_2 \).
What are majority and minority charge carriers of p-type and n-type semiconductors?
A plane wave travelling in a medium is incident on a plane surface separating this medium from a rarer medium. Draw a diagram to show refraction of the wave. Hence, verify Snell’s law.
Define ‘wavefront’ of a light wave. A plane wavefront is refracted from a convex lens. Draw the shape of the refracted wavefront.
Briefly explain how and where the displacement current exists during the charging of a capacitor.

For a short dipole placed at origin O, the dipole moment P is along the X-axis, as shown in the figure. If the electric potential and electric field at A are V and E respectively, then the correct combination of the electric potential and electric field, respectively, at point B on the Y-axis is given by:

For a short dipole placed at origin O
State any three characteristics of electromagnetic waves.
Differentiate between magnetic flux through an area and magnetic field at a point.
How will the magnetic field inside a long solenoid be affected when:
(i) the radius of the turns of the solenoid is increased,
(ii) the length of the solenoid as well as the total number of its turns are doubled?
A charged particle \(q\) moving with a velocity \( \mathbf{v} \) is subjected to a uniform magnetic field \( \mathbf{B} \) acting perpendicular to \( \mathbf{v} \). If a uniform electric field \( \mathbf{E} \) is also set up in the region along the direction of \( \mathbf{B} \), describe the path followed by the particle and draw its shape.
In the following nuclear reaction, \(^1_0\text{n} + ^{235}_{92}\text{U} \rightarrow ^{140}_{54}\text{Xe} + ^b_a\text{Sr} + 2(^1_0\text{n})\) we have
Which of the following statement(s) is/are true for p-type semiconductors?
(A) Holes are minority carriers and pentavalent atoms are the dopants.
(B) Electrons are majority carriers and trivalent atoms are the dopants.
(C) Holes are majority carriers and trivalent atoms are the dopants.
(D) Electrons are minority carriers and pentavalent atoms are the dopants.
Choose the correct answer from the options given below:
On connecting a device X in a series circuit with a battery and a resistor, a current passes through the circuit. On reversing the polarity of the battery, the current in the circuit drops to almost zero. The device X may be a
Below given are some statements about electronic devices:
(A) Diodes can be used for rectifying an ac voltage.
(B) For semiconductors, band gap energy E\(_g\) > 3 eV.
(C) By changing the external applied voltage, junction barriers can be changed.
(D) p-n junction is the 'key' to all semiconductor devices.
Choose the correct answer from the options given below:
Which of the following statements are correct?
(A) The electrostatic repulsive force between the protons can be greater than the nuclear force to bind the nucleons together inside a nucleus.
(B) The repulsive electrostatic force between protons in smaller nuclei is much smaller than the nuclear force between nucleons inside a nucleus.
(C) The gravitational force between nucleons is much smaller than the nuclear force between the nucleons inside a nucleus.
(D) The binding energy per nucleon between nucleons is almost constant because the nuclear force is a long range force.
Choose the correct answer from the options given below:
An electron in the ground state of a hydrogen atom absorbs 12.09 eV energy. The angular momentum of the electron increases by
Which of the following statements are correct?
(A) A nucleus of mass number A has a radius R given by the expression R = R\(_0\)A\(^{1/3}\)
(B) Volume of nucleus is proportional to mass number A
(C) The density of nucleus increases with the radius of nucleus.
(D) Density of nuclear matter does not depend on its mass number A
Choose the correct answer from the options given below:
The photoelectric current is directly proportional to the number of photo electrons emitted per second. This implies that
If focal length of a concave lens is 50 cm, then the power of the lens would be
Which of the following statements are correct?
(A) Total internal reflection occurs when a ray of light travels from a rarer transparent medium to a denser medium.
(B) In total internal reflection, the incident ray of light remains in the same medium after reflection.
(C) In total internal reflection, the angle of incidence inside the denser transparent medium is equal to the angle of reflection in the same medium.
(D) In total internal reflection inside a denser medium there is no angle of refraction
Choose the correct answer from the options given below:
A polaroid sheet is rotated between two crossed polarizers. The intensity of transmitted light would be maximum, when the angle between the axes of the first polarizer and the polaroid sheet is