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 = 1 \over \sqrt \mu _0 \in _0 . In the light of the above statements, choose the correct answer from the options given below.

Statement I is correct but Statement II is false

Both Statement I and Statement II are true

Both Statement I and Statement II are false

Statement I is incorrect but Statement II is true

Electromagnetic Waves PYQ — JEE Main 2022 · 27 Jun · Shift 2 · Q59 with Solution

View written solutionFree

Correct answer: C

Examine Statement I

Statement I says:

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.

This is the basic idea from Maxwell’s equations:
- A time-varying electric field produces a magnetic field.
- A time-varying magnetic field produces an electric field.
These mutually sustaining changing fields propagate through space as electromagnetic waves.

Therefore, Statement I is true.
Examine Statement II

Statement II says:

In a material medium, the EM wave travels with speed $v = \frac{1}{\sqrt{\mu_0 \varepsilon_0}}.$

But $\frac{1}{\sqrt{\mu_0 \varepsilon_0}} = c,$ which is the speed of electromagnetic waves in vacuum, not in a general material medium.

In a material medium, the speed is $v = \frac{1}{\sqrt{\mu \varepsilon}},$ where $\mu$ and $\varepsilon$ are the permeability and permittivity of the medium.

Hence, Statement II is false.
Conclusion
- Statement I: True
- Statement II: False
So the correct option is: $\boxed{\text{C}}$
Comparison with stored correct answer

Stored correct answer: C

My derived answer also is C, so they agree.

View written solutionFree

Correct answer: C

Examine Statement I

Statement I says:

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.

This is the basic idea from Maxwell’s equations:
- A time-varying electric field produces a magnetic field.
- A time-varying magnetic field produces an electric field.
These mutually sustaining changing fields propagate through space as electromagnetic waves.

Therefore, Statement I is true.
Examine Statement II

Statement II says:

In a material medium, the EM wave travels with speed $v = \frac{1}{\sqrt{\mu_0 \varepsilon_0}}.$

But $\frac{1}{\sqrt{\mu_0 \varepsilon_0}} = c,$ which is the speed of electromagnetic waves in vacuum, not in a general material medium.

In a material medium, the speed is $v = \frac{1}{\sqrt{\mu \varepsilon}},$ where $\mu$ and $\varepsilon$ are the permeability and permittivity of the medium.

Hence, Statement II is false.
Conclusion
- Statement I: True
- Statement II: False
So the correct option is: $\boxed{\text{C}}$
Comparison with stored correct answer

Stored correct answer: C

My derived answer also is C, so they agree.