Maxwell's equation describe the fundamental law of - Physics


Maxwell's equation describe the fundamental law of


  • Electricity only

  • Magnetism only

  • Mechanics

  • Both electricity only and magnetism only



Both electricity only and magnetism only


The fundamental laws of electricity and magnetism are described by Maxwell's equation.

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How are em waves produced by oscillating charges?

Write any two important properties of electromagnetic waves.

An em wave exerts pressure on the surface on which it is incident. Justify.

In a plane electromagnetic wave, the electric field oscillates sinusoidally at a frequency of 2.0 × 1010 Hz and amplitude 48 V m−1.

(a) What is the wavelength of the wave?

(b) What is the amplitude of the oscillating magnetic field?

(c) Show that the average energy density of the E field equals the average energy density of the B field. [c = 3 × 108 m s−1]

How is the speed of em-waves in vacuum determined by the electric and magnetic field?

Do electromagnetic waves carry energy and momentum ?

Identify the electromagnetic waves whose wavelengths vary as:

(a) 10–12 m < λ < 10–8 m

(b) 10–3 m < λ < 10–1 m

Write one use for each.

What is the ratio of the speed of gamma rays to that of radio waves in a vacuum?

How are electric vector `(vec "E")`, magnetic vector `(vec "B")` and velocity vector `(vec "C")` oriented in an electromagnetic wave?

Explain briefly how electromagnetic waves are produced by an oscillating charge. How is the frequency of the em waves produced related to that of the oscillating charge?

Write the following radiations in ascending order with respect to their frequencies:

X-rays, microwaves, UV rays and radio waves.

In a microwave oven, the food is kept in a plastic container and the microwaves is directed towards the food. The food is cooked without melting or igniting the plastic container. Explain.

Can an electromagnetic wave be deflected by an electric field or a magnetic field?

Can an electromagnetic wave be polarised?

An electromagnetic wave going through vacuum is described by
E = E0 sin (kx − ωt); B = B0 sin (kx − ωt).
Which of the following equations is true?

Speed of electromagnetic waves is the same

A laser beam has intensity 2.5 × 1014 W m−2. Find amplitudes of electric and magnetic fields in the beam.

The energy associated with light of which of the following colours is minimum : 

This is an example of step-up transformer .

Define frequency modulation and state any one advantage of frequency modulation (FM) over amplitude modulation (AM). 

State any one property which is common to all electromagnetic waves.

The energy levels of an atom of a certain element are shown in the given figure. Which one of the transitions A, B, C, D or E will result in the emission of photons of electromagnetic radiation of wavelength 618.75 nm? Support your answer with mathematical calculations.

An e.m. wave is propagating in a medium with a velocity `vec"v" = "v" hat"i"`. The instantaneous oscillating electric field of this e.m. wave is along +y-axis, then the direction of an oscillating magnetic field of the e.m. wave will be along:

Which of the following is an electromagnetic wave?

Write notes on Gauss' law in magnetism.

Give two uses of Microwaves.

Give two uses of UV radiation.

Write a short note on the microwave.

Write a short note on the radio waves.

Explain the importance of Maxwell’s correction.

Consider a parallel plate capacitor whose plates are closely spaced. Let R be the radius of the plates and the current in the wire connected to the plates is 5 A, calculate the displacement current through the surface passing between the plates by directly calculating the rate of change of flux of electric field through the surface.

Let an electromagnetic wave propagate along the x-direction, the magnetic field oscillates at a frequency of 1010 Hz and has an amplitude of 10-5 T, acting along the y – direction. Then, compute the wavelength of the wave. Also write down the expression for the electric field in this case.

Which one of the following does not represent simple harmonic motion? Here y denotes the instantaneous displacement. Here, A and B are constants and co is the angular frequency.

In space communication, the sound waves can be sent from one place to another

A plane electromagnetic wave travels in free space along x-axis. At a particular point in space, the electric field along y-axis is 9.3 Vm−1. The magnetic induction (B) along z-axis is:

An accelerate electron would produce.

The velocity of light in vacuum can be changed by changing

The velocity of electromagnetic wave is parallel to

Which of the following are not electromagnetic waves?

Dimensions of ε0 `(d phi_ε)/(dt)` are of

For which frequency of light, the eye is most sensitive?

Electromagnetic waves are produced by ______.

Which of the following type of radiations are radiated by an oscillating electric charge?

For a plane electromagnetic wave propagating in x-direction, which one of the following combinations gives the correct possible directions for electric field (E) and magnetic field (B) respectively?

For a plane electromagnetic wave propagating in the x-direction, which one of the following combinations gives the correct possible directions for the electric field (E) and magnetic field (B) respectively?

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

  1. Ex, By.
  2. Ey, Bz.
  3. Bx, Ey.
  4. Ex, By.

Professor C.V Raman surprised his students by suspending freely a tiny light ball in a transparent vacuum chamber by shining a laser beam on it. Which property of EM waves was he exhibiting? Give one more example of this property.

A plane EM wave travelling in vacuum along z direction is given by `E = E_0 sin(kz - ωt)hati` and `B = B_0 sin(kz - ωt)hatj` 

  1. Evaluate `oint E.dl` over the rectangular loop 1234 shown in figure.
  2. Evaluate `int B.ds` over the surface bounded by loop 1234.
  3. Use equation `oint E.dl = (-dphi_B)/(dt)` to prove `E_0/B_0` = c.
  4. By using similar process and the equation `ointB.dl = mu_0I + ε_0 (dphi_E)/(dt)`, prove that c = `1/sqrt(mu_0ε_0)`

The intensity of the light from a bulb incident on a surface is 0.22 W/m2 . The amplitude of the magnetic field in this light-wave is ______× 10–9 T. 

(Given: Permittivity of vacuum ε0 = 8.85 × 10–12 C2 N–1 – m–2, speed of light in vacuum c = 3 × 108 ms-1)

A plane electromagnetic wave of frequency 500 MHz is travelling in a vacuum along a y-direction.

At a particular point in space and time, `vec"B"` = 8.0 × 10-8 `hat"Z"`T. The value of the electric field at this point is ______.

(speed of light = 3 × 108 ms-1)

`hat x, hat y, hat z` are unit vectors along x, y, and Z directions.

For an electromagnetic wave travelling in free space, the relation between average energy densities due to electric (Ue) and magnetic (Um) fields is ______.

A plane electromagnetic wave, has frequency of 2.0 × 1010 Hz and its energy density is 1.02 × 10-8 J/m3 in vacuum. The amplitude of the magnetic field of the wave is close to `(1/(4piepsilon_0) = 9xx10^9"Nm"^2/"C"^2  "and speed of light" = 3 xx 10^8  "m"  "s"^-1)`:

Sunlight falls normally on a surface of area 36 cm2 and exerts an average force of 7.2 × 10-9 N within a time period of 20 minutes. Considering a case of complete absorption the energy flux of incident light is ______.

The electric field in an electromagnetic wave is given by E = 56.5 sin ω(t - x/c)Nc-1. Find the intensity of the wave if it is propagating along x-axis in the free space.

(Given ε0 = 8.85 × 10-12 C2 N-1 m-2)

A plane electromagnetic wave with frequency of 30 MHz travels in free space. At particular point in space and time, electric field is 6 V/m. The magnetic field at this point will be x × 10-8 T. The value of x is ______.

An electromagnetic wave of frequency 3 GHz enters a dielectric medium of relative electric permittivity 2.25 from vacuum. The wavelength of this wave in that medium will be ______ × 10-2 cm. 

In a plane electromagnetic wave, the direction of electric field and magnetic field are represented by `hat"k"` and 2`hat"i" - 2hat"j"`, respectively. What is the unit vector along direction of propagation of the wave.

An electromagnetic wave of frequency v = 3.0 MHz passes from vacuum into a dielectric medium with permittivity ∈ = 4.0. Then ______.

Name the electromagnetic wave/radiation which is used to study crystal structure.


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