Consider the charge configuration as shown in the figure. Calculate the electric field at point A. If an electron is placed at points A, what is the acceleration experienced by this electron? (mass of the electron = 9.1 x 10^-31 kg and charge of electron = −1.6 x 10^-19 C)

The following pictures depict electric field lines for various charge configurations.


(i) In figure (a) identify the signs of two charges and find the ratio \(\left| \frac { { q }_{ 1 } }{ { q }_{ 2 } } \right| \)
(ii) In figure (b), calculate the ratio of two positive charges and identify the strength of the electric field at three points A, B, and C
(iii) Figure (c) represents the electric field lines for three charges. If q₂ = -20 nC, then calculate the values of q₁ and q₃.

A copper wire of cross-sectional area 0.5 mm² carries a current of 0.2 A. If the free electron density of copper is 8.4 x 10²⁸ m^-3 then compute the drift velocity of free electrons.

For the given circuit find the value of I.

Calculate the currents in the following circuit.

Compute the magnetic length of a uniform bar magnet if the geometrical length of the magnet is 12 cm. Mark the positions of magnetic pole points.

If the current i flowing in the straight conducting wire as shown in the figure decreases, find out the direction of induced current in the metallic square loop placed near it.

How will you define Q-factor?

What is displacement current?

Write notes on Ampere-Maxwell law.

Why do stars twinkle?

Why does sky appear blue?

An electron and an alpha particle have same kinetic energy. How are the de Broglie wavelengths associated with them related?

When light of wavelength 2200 Å falls on Cu, photo electrons are emitted from it. Find
(i) the threshold wavelength and
(ii) the stopping potential.
Given: the work function for Cu is ϕ₀ = 4.65 eV.

What is isobar? Give an example.

Consider two hydrogen atoms H_A and H_B in ground state. Assume that hydrogen atom H_A is at rest and hydrogen atom H_B is moving with a speed and make head-on collision with the stationary hydrogen atom H_A. After the collision, both of them move together. What is minimum value of the kinetic energy of the moving hydrogen atom H_B, such that any one of the hydrogen atoms reaches first excitation state.

What are black holes?

Write a short note on quantum theory of light.

What is call 'grating element'?

A transmitting antenna has a height of 40 m and the height of the receiving antenna is 30 m. What is the maximum distance between them for line-of-sight communication? The radius of the earth is 6.4 × 10⁶ m.

A diode is called as a unidirectional device. Explain.

In the combination of the following gates, write the Boolean equation for output Y in terms of inputs A and B.

When does a dielectric said to be polarized?

How is sign convention followed while applying Kirchhoff's first rule?

Define remanence or retentivity?

A graph of magnetic flux (Ф) versus current CI is shown for two inductors A & B, which has a larger value of self-inductance?

Why are Infrared radiation referred to as heatwaves? Name the radiations, which are next to these radiation having
(i) shorter λ
(ii) longer λ.

A polaroid (I) is placed in front of a monochromatic source. Another polaroid (II) is placed in front of this polaroid (I) and rotated till no light passes. A third polaroid (III) is now placed in between (I) and (II). In this case, will light emerge from (II)? Explain

A biconvex lens has focal length f and intensity of light I passing through it. What will be the focal length and intensity for portions of lenses obtained by cutting it vertically and horizontally as shown in figure?

How does the maximum kinetic energy of electrons emitted vary with the work function of the metal?