Choose the correct option relating wave lengths of different parts of electromagnetic wave spectrum:

\lambda radio waves > \lambda micro waves > \lambda visible > \lambda x-rays

\lambda visible > \lambda x-rays > \lambda radio waves > \lambda micro waves

\lambda visible < \lambda micro waves < \lambda radio waves < \lambda x-rays

\lambda x-rays < \lambda micro waves < \lambda radio waves < \lambda visible

Electromagnetic Waves PYQ — JEE Main 2020 · 4 Sep · Shift 1 · Q46 with Solution

View written solutionFree

Correct answer: A

Recall the order of the electromagnetic spectrum by wavelength

In the electromagnetic spectrum, wavelength decreases in the following order:
$\text{Radio waves} > \text{Microwaves} > \text{Infrared} > \text{Visible} > \text{Ultraviolet} > \text{X-rays} > \gamma\text{-rays}$
Extract only the waves mentioned in the options

From the above order, considering only radio waves, microwaves, visible light, and X-rays:
$\lambda_{\text{radio}} > \lambda_{\text{microwave}} > \lambda_{\text{visible}} > \lambda_{\text{x-rays}}$
Compare with the given options
- Option A: $\lambda$ radio waves $>$ $\lambda$ micro waves $>$ $\lambda$ visible $>$ $\lambda$ x-rays
  This matches exactly.
- Option B: says visible has greater wavelength than X-rays, but then puts radio and microwaves smaller than them — incorrect.
- Option C: puts X-rays as having the largest wavelength — incorrect.
- Option D: puts visible as the largest after radio and microwaves, but the order is wrong overall — incorrect.
Final answer

The correct option is:
$\boxed{\text{A}}$

View written solutionFree

Correct answer: A

Recall the order of the electromagnetic spectrum by wavelength

In the electromagnetic spectrum, wavelength decreases in the following order:
$\text{Radio waves} > \text{Microwaves} > \text{Infrared} > \text{Visible} > \text{Ultraviolet} > \text{X-rays} > \gamma\text{-rays}$
Extract only the waves mentioned in the options

From the above order, considering only radio waves, microwaves, visible light, and X-rays:
$\lambda_{\text{radio}} > \lambda_{\text{microwave}} > \lambda_{\text{visible}} > \lambda_{\text{x-rays}}$
Compare with the given options
- Option A: $\lambda$ radio waves $>$ $\lambda$ micro waves $>$ $\lambda$ visible $>$ $\lambda$ x-rays
  This matches exactly.
- Option B: says visible has greater wavelength than X-rays, but then puts radio and microwaves smaller than them — incorrect.
- Option C: puts X-rays as having the largest wavelength — incorrect.
- Option D: puts visible as the largest after radio and microwaves, but the order is wrong overall — incorrect.
Final answer

The correct option is:
$\boxed{\text{A}}$