Use app×
Join Bloom Tuition
One on One Online Tuition
JEE MAIN 2025 Foundation Course
NEET 2025 Foundation Course
CLASS 12 FOUNDATION COURSE
CLASS 10 FOUNDATION COURSE
CLASS 9 FOUNDATION COURSE
CLASS 8 FOUNDATION COURSE
0 votes
102 views
in General by (240k points)
closed by

The electric field in an electro-magnetic wave (in vacuum) is described by E = Emax sin(Kx - ωt)

Where

Emax = 100 N/C and K = 1 × 107 m-1, speed of light is 3 × 108 m/s.

What is the amplitude of the corresponding magnetic wave?


1. 4.57 × 10-7 T
2. 2.99 × 10-7 T
3. 3.33 × 10-7 T
4. 2.99 × 107 T

1 Answer

0 votes
by (238k points)
selected by
 
Best answer
Correct Answer - Option 3 : 3.33 × 10-7 T

Concept:

The intrinsic impedance of the wave is defined as the ratio of the electric field and the magnetic field phasor (complex amplitude), i.e.

\(η =\frac{E}{H}\)

For free-space, the intrinsic impedance is a real quantity, i.e.

η  = η0 = 120π

Analysis:

E = Emax sin(Kx - ωt)

With Emax = 100 N/C, the magnetic field will be:

With \(η =\frac{E}{H}\):

\(H =\frac{E}{\eta}\)

\(H =\frac{100}{120\pi}A/m\)

B = μ0 H

\(B=4\pi × 10^{-7}× \frac{100}{120\pi }\)

B = 3.33 × 10-7 T

Welcome to Sarthaks eConnect: A unique platform where students can interact with teachers/experts/students to get solutions to their queries. Students (upto class 10+2) preparing for All Government Exams, CBSE Board Exam, ICSE Board Exam, State Board Exam, JEE (Mains+Advance) and NEET can ask questions from any subject and get quick answers by subject teachers/ experts/mentors/students.

Categories

...