One requires 11 \(eV\) of energy to dissociate a carbon monoxide molecule into carbon and oxygen atom. The minimum frequency of the appropriate electromagnetic radiation to achieve the dissociation lines in

If \({ \mu }_{ 0 }\) be the permeability and \({ k }_{ 0 }\) the dielectric constant of a medium. its refractive index in given by

The kinetic energy of a photon of frequency v, rest mass.\({ m }_{ 0 }\) having mass m while moving with velocity v is

The electric field associated with an e.m. wave in vacuum is given by \(\overset { \rightarrow }{ E } =\hat { i } 40 \ cos(kz-6\times { 10 }^{ 8 }t)\) where E,z, and t are in volt/m. metre and seconds respectively. The value of wave factor k is:

The correct option if in vacuum the speed of gamma rays, x-rays and microwaves are \({ v }_{ g }, \ { v }_{ x }and \ { v }_{ m }\)

If a source of power 4 KW produces \({ 10 }^{ 20 }\) Photon/second, the radiation belongs to part of the spectrum called

If \({ \mu }_{ 0 },{ \mu }_{ r },{ \epsilon }_{ 0 }and{ { \epsilon }_{ r } }\) as the absolute permeability relative permeability, absolute permittivity and relative permittivity of the medium, then the velocity of electromagnetic wave in a medium is

Sun also sends electromagnetic waves to earth. which one of the electromagnetic waves out of the visible portion, from the sun will be reaching the surface of earth earlier than others:

The radiation force on the roof is 

If you find close loops of \(\overset { \rightarrow }{ B } \) in a region in space, does it necessarily mean that actual charges are flowing across the area bounded by the loops?

Give the ratio of velocities of light rays of  wavelength 4000 \(\dot { A } \) and 8000 \(\dot { A } \) in vacuum.

The electromagnetic waves of frequency range from 5 x 10⁵ Hz to 10⁹  Hz are called..........

Name the physical quantity which remains same for microwaves of wavelength 1 mm and UV radiations of 1600 \(\mathring { A } \) in vacuum.

A parallel capacitor is being charged by a time-varying current. Explain briefly how Ampere's circuital law is generalised to incorporate the effect due to the displacement current.

When an ideal capacitor is charged by a DC battery, no current flows. However, when an AC source is used, the current flows continously. How does one explain this, based on the concept of displacement current?

Calculate the displacement currecnt between the square plates of side 1 cm of a capcitor, if electric field between the plates is changing at the rate of 3 x 10⁶ V m^-1 s^-1.

Draw a sketch of a plane electromagnetic wave propagating along the z-direction. Depict clearly the directions of electric and magnetic fields varying sinusoidally with z.

Arrange the following electromagnetic radiatios in ascending order to their frequencies:
(i) Microwaves
(ii) Radio waves
(iii) X-rays
(iv) Gamma rays
Write two uses of any one of these.

There are some famous numbers associated with electromagnetic radiations in different contexts in Physics given below. State the part of the electromnagnetic spectrum to which each belongs.
(i) 21 cm (wavelength emitted by atomic hydrogen in interstellar space).
(ii) 1057 MHz (frequency of radiation arising from two close energy levels in hydrogen, known as Lamb shift ).
(iii) 2.7 K (temperature associated with the isotropic radiation filling all space thought to be a relic of the big-bang origin of the universe).
(iv) 5890 \(\overset{\circ}{A}\) - 5896 \(\overset{\circ}{A}\) (double lines of sodium).
(v) 14.4 keV (energy of a particular transition in ⁵⁷Fe nucleus associated with a famous high resolution spectroscopic method (Mössbauer spectroscopy).

Figure shows a capacitor made of two circular plates each of radius 12 cm and separated by 5.0 cm. The capacitor is being charged by an external source (not shown in the figure). The charging current is constant and equal to 0.15 A.
(i) Calculate the capacitance and the rate of change of potential difference between the plates.
(ii) Is Kirchhoff's first rule (junction rule) valid at each plate of the capacitor? Explain.

Write the expression for the generalised form of Ampere's circuital law.
Discuss its significance and describe briefly how the concept of displacement current is explained through charging/discharging of a capacitor in an electric circuit.

The electric field intensity produced by the radiations coming from 100 W bulb at a 3m distance is E.What will be the electric field produced by the radiations coming from 50 W bulb at the same distance?

A plane EM wave travelling along \(z\) direction is described by \(\overset { \rightarrow }{ E } ={ E }_{ 0 } \ sin \ (kz-\omega t)i\) and \(\overset { \rightarrow }{ B } ={ B }_{ 0 } \ sin \ (kz-\omega t)\overset { \rightarrow }{ j } \). Show that
(i) The average energy density of the wave is given by \({ U }_{ av }=\frac { 1 }{ 4 } { \varepsilon }_{ 0 }{ E }_{ 0 }^{ 2 }+\frac { 1 }{ 4 } \frac { { B }_{ 0 }^{ 2 } }{ { \mu }_{ 0 } } \) 
(ii) The time-averaged intensity  of the wave is given by \({ I }_{ av }=\frac { 1 }{ 2 } c\varepsilon _{ 0 }{ E }_{ 0 }^{ 2 }\).

A parallel plate capacitor made of circular plates each of radius 10.0 cm has a capacitance 200 pF. The capacitor is connected to a 200 V a.c. supply with an angular frequency of 200 rad s^-1.
(a) What is the r.m.s value of the conduction current?
(b) Is the conduction current equal to displacement current?
(c) Peak value of displacement current.
(d) Determine the amplitude of magnetic field at a point 2.0 cm from the axis between the plates.