Consider a point charge +q placed at the origin and another point charge -2q placed at a distance of 9 m from the charge +q. Determine the point between the two charges at which electric potential is zero.

Two electric bulbs marked 20 W – 220 V and 100 W – 220 V are connected in series to 440 V supply. Which bulb will get fused?

What is the magnetic field at the centre of the loop shown in figure?

A rectangular coil of area 70 cm² having 600 turns rotates about an axis perpendicular to a magnetic field of 0.4 Wb m^–2. If the coil completes 500 revolutions in a minute, calculate the instantaneous emf when the plane of the coil is
(i) perpendicular to the field
(ii) parallel to the field and
(iii) inclined at 60^o with the field.

A 400 mH coil of negligible resistance is connected to an AC circuit in which an effective current of 6 mA is flowing. Find out the voltage across the coil if the frequency is 1000 Hz.

Two air core solenoids have the same length of 80 cm and same cross-sectional area 5 cm². Find the mutual inductance between them if the number of turns in the first coil is 1200 turns and that in the second coil is 400 turns.

A magnetron in a microwave oven emits electromagnetic waves (em waves) with frequency f = 2450 MHz. What magnetic field strength is required for electrons to move in circular paths with this frequency?

A pulse of light of duration 10⁻⁶ s is absorbed completely by a small object initially at rest. If the power of the pulse is 60\(\times\) 10⁻³ W. Calculate the final momentum of the object.

In Young's double slit experiment, 62 fringes are seen in visible region for sodium light of wavelength 5893 Å. If violet light of wavelengtlt 4359 Å is used in place of sodium light, then what is the number of fringes seen?

Lights of two wavelengths 560 nm and 420 nm are used in Young’s double slit experiment. Find the least distance from the central fringe where the bright fringes of the two wavelengths coincide. Given D = 1 m and d = 3 mm.

Calculate the maximum kinetic energy and maximum velocity of the photoelectrons emitted when the stopping potential is 81 V for the photoelectric emission experiment.

A 3310 Å photon liberates an electron from a material with energy 3 x10^-19 J while another 5000 Å photon ejects an electron with energy 0.972 x 10^-19 J from the same material. Determine the value of Planck’s constant and the threshold wavelength of the material.

Calculate the radius of the earth if the density of the earth is equal to the density of the nucleus.[mass of earth 5.97 x 10²⁴ kg].

Compute the binding energy per nucleon of  \(_{ 2 }^{ 4 }{ He }\) nucleus.

Prove the Boolean identity AC + ABC = AC and give its circuit description.