Show that average energy density of the electric field E → equals the average energy density of the magnetic field B → .

The formula of average energy density due to the magnetic field is, U B = 1 2 μ 0 B 0 2 , and the formula of average energy density due to the electric field is, U E = 1 2 ε 0 E 0 2 , but we know that the relation between electric field and magnetic field, E 0 = B 0 c , here c = 1 μ 0 ε 0 . It means, U B = 1 2 μ 0 E 0 2 c 2 = 1 2 μ 0 E 0 2 1 μ 0 ε 0 2 = 1 2 ε 0 E 0 2 ⇒ 1 2 ε 0 E 0 2 = U E = U B

Show that average energy density of the electric field E → equals the average energy density of the magnetic field B → .

The formula of average energy density due to the magnetic field is, U B = 1 2 μ 0 B 0 2 , and the formula of average energy density due to the electric field is, U E = 1 2 ε 0 E 0 2 , but we know that the relation between electric field and magnetic field, E 0 = B 0 c , here c = 1 μ 0 ε 0 . It means, U B = 1 2 μ 0 E 0 2 c 2 = 1 2 μ 0 E 0 2 1 μ 0 ε 0 2 = 1 2 ε 0 E 0 2 ⇒ 1 2 ε 0 E 0 2 = U E = U B

Two students A and B prepare the following table about the electromagnetic waves. Rewrite this table in its corrected form. Student Direction of Peak Value of Electric field Magnetic field Propagation Electric field Magnetic field A Along x -axis Along z -axis Along y -axis E 0 B 0 = c E 0 B Along y -axis Along x -axis Along x -axis E 0 = c B 0 B 0

In an electromagnetic wave, the electric and magnetic field vectors oscillate, perpendicular to the direction of propagation of the wave. This is called the transverse nature of electromagnetic waves. The given wave in electromagnetic waves. Electromagnetic radiation is a self-propagating wave in space with electric and magnetic components. These components oscillate at right angles to each other and to the direction of propagation. The direction of the electromagnetic waves can be determined by the formula, E → × B → . And the formula of the speed of light in terms of the magnitude of electric field and magnetic field will be, c = E 0 B 0 . So the correct table, Student Direction of Peak Value of Electric field Magnetic field Propagation Electric field Magnetic field A Along x -axis Along z -axis Along negative y -axis E 0 B 0 = E 0 c B Along y -axis Along x -axis Along negative z -axis E 0 = c B 0 B 0

MEDIUM

NEET

IMPORTANT

Earn 100

Show that average energy density of the electric field $\vec{E}$ equals the average energy density of the magnetic field $\vec{B}$ .

Important Questions on Electromagnetic Waves

EASY

NEET

IMPORTANT

Gamma Question Bank for Medical Physics>Chapter 23 - Electromagnetic Waves>Assignment>Q 19

A variable frequency ac source Is connected to a capacitor. How will the displacement current change with decrease in frequency?

EASY

NEET

IMPORTANT

Gamma Question Bank for Medical Physics>Chapter 23 - Electromagnetic Waves>Assignment>Q 20

How can you conclude that electromagnetic wave is transverse in nature? Draw a diagram showing the propagation of an electromagnetic wave along the

x

-axis, indicating clearly the directions of the oscillating electric and magnetic fields associated with it.

EASY

NEET

IMPORTANT

Gamma Question Bank for Medical Physics>Chapter 23 - Electromagnetic Waves>Assignment>Q 21

Define the intensity of electromagnetic wave? Write its formula in terms of r.m.s. value of electric field.

EASY

NEET

IMPORTANT

Gamma Question Bank for Medical Physics>Chapter 23 - Electromagnetic Waves>Assignment>Q 22

Two students A and B prepare the following table about the electromagnetic waves. Rewrite this table in its corrected form.

Student	Direction of			Peak Value of
	Electric field	Magnetic field	Propagation	Electric field	Magnetic field
A	Along $x$ -axis	Along $z$ -axis	Along $y$ -axis	$E_{0}$	$B_{0} = c E_{0}$
B	Along $y$ -axis	Along $x$ -axis	Along $x$ -axis	$E_{0} = c B_{0}$	$B_{0}$

MEDIUM

NEET

IMPORTANT

Gamma Question Bank for Medical Physics>Chapter 23 - Electromagnetic Waves>Assignment>Q 23

The electric field of a plane electromagnetic wave in vacuum is represented by

E_{y} = 0.5 \cos [2 π \times 10^{8} (t - \frac{x}{c})]

(i) What is the direction of propagation of electromagnetic wave?
(ii) Determine the wavelength of the wave.
(iii) Calculate the component of associated magnetic field.

MEDIUM

NEET

IMPORTANT

Gamma Question Bank for Medical Physics>Chapter 23 - Electromagnetic Waves>Assignment>Q 24

Calculate displacement current between the square plates of side,

1 cm

of a capacitor of the electric field between the plates is changing at the rate of

3 \times 10^{6} V m^{- 1} s^{- 1}

EASY

NEET

IMPORTANT

Gamma Question Bank for Medical Physics>Chapter 23 - Electromagnetic Waves>Assignment>Q 26

The R.M.S. value of an electric field of the light coming from the sun is

720 N C^{- 1}

. Calculate the average total energy density of the electromagnetic wave.

MEDIUM

NEET

IMPORTANT

Gamma Question Bank for Medical Physics>Chapter 23 - Electromagnetic Waves>Assignment>Q 27

What is microwave oven? Explain its principle of working,

Show that average energy density of the electric field E→ equals the average energy density of the magnetic field B→.

Important Questions on Electromagnetic Waves

Learn and Prepare for any exam you want !

Show that average energy density of the electric field $\vec{E}$ equals the average energy density of the magnetic field $\vec{B}$ .