Electromagnetic Waves

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New answer posted•a year ago

Electromagnetic Waves Physics NCERT Exemplar Solutions Class 12th Chapter Eight

Match List – I with List – II:

List – I List – II

(A) UV rays (i) Diagnostic tool in medicine

(B) X-rays(ii) Water purification

(C) Microwave(iii) Communication, Radar

(D) Infrared wave(iv) Improving visibility in foggy daya

Choose the correct answer from the options given below:

4 Views|Posted a year ago

Asked by Vishal Baghel

Answered by

Vishal Baghel | Contributor-Level 10

a year ago

Based an theoretical data.

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New answer posted•a year ago

Electromagnetic Waves Physics NCERT Exemplar Solutions Class 12th Chapter Eight

The electric field of a plane electromagnetic wave is given by $\overset{?}{E} = E_{0} (\hat{x} + \hat{y}) s i n ? (k z - ω t)$ Its magnetic field will be given by:

7 Views|Posted a year ago

Asked by Alok Kumar Singh

Answered by

Alok Kumar Singh | Contributor-Level 10

a year ago

Kindly go through the solution

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New answer posted•a year ago

Electromagnetic Waves Physics NCERT Exemplar Solutions Class 12th Chapter Eight

Given below are two statements:

Statement I : A time varying electric field is a source of changing magnetic field and vice-versa. Thus a disturbance in electric or magnetic field creates EM waves.

Statement II : In a material medium, the EM wave travels with speed v = $\frac{1}{\sqrt[]{μ_{0} \in_{0}}} .$  In the light of the above statements, choose the correct answer for the options given below

6 Views|Posted a year ago

Asked by Payal Gupta

Answered by

Payal Gupta | Contributor-Level 10

a year ago

Statement 1 is true

Speed of EM ware in vaccum is given by,

$C = \frac{1}{\sqrt[]{μ_{0} \in_{0}}}$

Speed of EM wave in a material medium

$v = \frac{1}{\sqrt[]{u_{r} μ_{0} \in_{r} \in_{0}}}$

So, statement (2) is false.

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New answer posted•a year ago

Electromagnetic Waves Physics NCERT Exemplar Solutions Class 12th Chapter Eight

An EM wave of intensity I falls on a surface kept in vacuum and exerts radiation pressure p on it. Which of the following are true?

(a) Radiation pressure is I/c if the wave is totally absorbed

(b) Radiation pressure is —I/c if the wave is totally reflected

(c) Radiation pressure is 2I/c if the wave is totally reflected

(d) Radiation pressure is in the range I/c < p < 2I/c for real surfaces

4 Views|Posted a year ago

Asked by Payal Gupta

Answered by

Payal Gupta | Contributor-Level 10

a year ago

This is a multiple choice answer as classied in NCERT Exemplar

momentum per unit time per unit area = intensity/ speed of wave

= I/c= radiation pressure (p)

Momentum is always double when a light gets reflected back as in that case the momentum which is positive to one side added to momentum whic

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New answer posted•a year ago

Electromagnetic Waves Physics NCERT Exemplar Solutions Class 12th Chapter Eight

The source of electromagnetic waves can be a charge

(a) Moving with a constant velocity

(b) Moving in a circular orbit

(c) At rest

(d) Falling in an electric field

3 Views|Posted a year ago

Asked by Payal Gupta

Answered by

Payal Gupta | Contributor-Level 10

a year ago

(b, d) Here, in option (b) charge is moving in a circular orbit.

In circular motion, the direction of the motion of charge is changing continuously, thus it is an accelerated motion and this option is correct.

Also, we know that a charge starts accelerating when it falls in an electric field.

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New answer posted•a year ago

Electromagnetic Waves Physics NCERT Exemplar Solutions Class 12th Chapter Eight

A charged particle oscillates about its mean equilibrium position with a frequency of 10⁹ The electromagnetic waves produced

(a) Will have frequency of 10⁹Hz

(b) Will have frequency of 2 x 10⁹ Hz

(c) Will have wavelength of 0.3 m

(d) Fall in the region of radio waves

6 Views|Posted a year ago

Asked by Payal Gupta

Answered by

Payal Gupta | Contributor-Level 10

a year ago

This is a multiple choice answer as classified in NCERT Exemplar

(a, c, d) as we know that $λ = \frac{c}{υ}$ = $\frac{3 \times 10^{8}}{10^{9}}$ = 0.3m and it is fall in region of radio wave.

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New answer posted•a year ago

Electromagnetic Waves Physics NCERT Exemplar Solutions Class 12th Chapter Eight

A plane electromagnetic wave propagating along x-direction can have the following pairs of E and B.

(a) E_x, B_y

(b) E_y, B_z

(c) B_x,E_y

(d) E_z,B_y

8 Views|Posted a year ago

Asked by Payal Gupta

Answered by

Payal Gupta | Contributor-Level 10

a year ago

This is a multiple choice answer as classified in NCERT Exemplar

(b, d) As electric and magnetic field vectors E and B are perpendicular to each other as well as Perpendicular to the direction of propagation of electromagnetic wave.

Here in the question electromagnetic wave is propagating along x-dir

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New answer posted•a year ago

Electromagnetic Waves Physics NCERT Exemplar Solutions Class 12th Chapter Eight

An electromagnetic wave travelling along z-axis is given as E=E₀cos(kz-wt).choose the correct options from the following

(a) Tha associated magnetic field is given as B=1/ck $\times$ E=1/w(k $\times E$ )

(b) The electromagnetic field can be written in terms of associated magnetic field as E=c(b $\times k$ )

(c) E=0,k.B=0

(d) K $\times$ E=0,k $\times B = 0$

6 Views|Posted a year ago

Asked by Payal Gupta

Answered by

Payal Gupta | Contributor-Level 10

a year ago

This is a multiple choice answer as classified in NCERT Exemplar

(a, b, c) electromagnetic wave traveling along the z direction is given by

E=E₀cos (kz-wt)

The associated magnetic field B in electromagnetic wave is along xaxis along k $\times E$

B₀=E₀/c=1/c (k $\times E$ )

E=c (B $\times k$ ) .As the angle is 90 so value is zero.

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New answer posted•a year ago

Electromagnetic Waves Physics NCERT Exemplar Solutions Class 12th Chapter Eight

An electromagnetic wave travels in vacuum along z-direction E= (E₁iE₂j)cos(kz-wt). Choose the correct options from the following

(a) The associated magnetic field is given as B= (E₁i-E₂j)cos(kz-wt)

(b) The associated magnetic field is given as B= (E₁i-E₂j)cos(kz-wt)

(c) The given electro magnetic field is circularly polarised

(d) The given electromagnetic wave is plane polarised

5 Views|Posted a year ago

Asked by Payal Gupta

Answered by

Payal Gupta | Contributor-Level 10

a year ago

This is a multiple choice answer as classified in NCERT Exemplar

(d) as the electric and magnetic field in electromagnetic wave are perpendicular to each other also they are perpendicular to wave propagation so they are plane polarised.

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New answer posted•a year ago

Electromagnetic Waves Physics NCERT Exemplar Solutions Class 12th Chapter Eight

An EM wave radiates outwards from a dipole antenna, with E₀as the amplitude of its electric field vector. The electric field E₀ which transports significant energy from the source falls off as

(a) 1/r³

(b) 1/r²

(c) 1/r

(d) Remains constant

7 Views|Posted a year ago

Asked by Payal Gupta

Answered by

Payal Gupta | Contributor-Level 10

a year ago

This is a multiple choice answer as classified in NCERT Exemplar

(c) From a diode antenna, the electromagnetic waves are radiated outwards.The amplitude of electric field vector Eo which transports significant energy from the source falls off intensity inversely as the distance from the antenna, i.e

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