SATHEE: Modern Physics 7 Question 67

Modern Physics 7 Question 67

15. A plane electromagnetic wave travels in free space along the $x$ -direction. The electric field component of the wave at a particular point of space and time is $E = 6 V m^{- 1}$ along $y$ -direction. Its corresponding magnetic field component, $B$ would be

(Main 2019, 8 April I)

(a) $2 \times 10^{- 8} T$ along $z$ -direction

(b) $6 \times 10^{- 8} T$ along $x$ -direction

(d) $2 \times 10^{- 8} T$ along $y$ -direction

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Solution:

Key Idea For an electromagnetic wave, ratio of magnitudes of electric and magnetic field is

$\frac{E}{B} = c$

where, $c$ is the speed of electromagnetic wave in vacuum.

Given, $E = 6 V / m, c = 3 \times 10^{8} m s^{- 1}$

So, $B = \frac{E}{c} = \frac{6}{3 \times 10^{8}} = 2 \times 10^{- 8} T$

Also, direction of propagation of electromagnetic wave is given by

$\hat{n} = E \times B$

Here, $\hat{n} = \hat{i}$ and $E =$ Unit vector of electric field $(\hat{j})$

$B =$ unit vector of magnetic field.

$\Rightarrow \hat{i} = \hat{j} \times B \Rightarrow B = \hat{k}$

Hence, magnetic field components,

$B = 2 \times 10^{- 8} \hat{k} T = 2 \times 10^{- 8} T$

(along $z$ -direction)

Modern Physics 7 Question 67

15. A plane electromagnetic wave travels in free space along the $x$ -direction. The electric field component of the wave at a particular point of space and time is $E = 6 V m^{- 1}$ along $y$ -direction. Its corresponding magnetic field component, $B$ would be

Solution:

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Modern Physics 7 Question 67

15. A plane electromagnetic wave travels in free space along the x-direction. The electric field component of the wave at a particular point of space and time is E=6Vm−1 along y-direction. Its corresponding magnetic field component, B would be

Solution:

Engineering Preparation

Medical Preparation

NCERT Books & Solutions

Important Resources

Other Resources

Syllabus

Test Platform

Sample Mock Test

Mentorship

NCERT Exercise Video Solution

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15. A plane electromagnetic wave travels in free space along the $x$ -direction. The electric field component of the wave at a particular point of space and time is $E = 6 V m^{- 1}$ along $y$ -direction. Its corresponding magnetic field component, $B$ would be