Question

The CORRECT statement among the following regarding electromagnetic waves is

• A. They can travel through vacuum
• B. They consist of only electric field
• C. They consist of only magnetic field
• D. They require a medium to propagate
• E. They move with a velocity of $3 \times 10^8 \text{ cms}^{-1}$

Hint:

Remember: EM waves are transverse in nature and propagate through vacuum at the speed of light. Light itself is an EM wave!

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Electromagnetic waves are oscillations of coupled electric and magnetic fields that propagate through space. We need to identify their fundamental characteristics.
Step 2: Key Formula or Approach:
Recall theoretical facts regarding EM waves:
They consist of mutually perpendicular oscillating electric and magnetic fields.
They do not require any material medium (they travel through the vacuum of space).
Their speed in a vacuum is \(c \approx 3 \times 10^8 \text{ ms}^{-1}\) (meters, not centimeters).
Step 3: Detailed Explanation:
Evaluating the options:
(A) They can travel through vacuum. (True - light from the sun reaches Earth).
(B) They consist of only electric field. (False - they contain both fields).
(C) They consist of only magnetic field. (False - they contain both fields).
(D) They require a medium to propagate. (False - unlike sound waves, EM waves don't need a physical medium).
(E) They move with a velocity of \(3 \times 10^8 \text{ cm s}^{-1}\). (False - the unit is meters per second; in cm/s it would be \(3 \times 10^{10}\)).
Step 4: Final Answer:
They can travel through vacuum.