Arrange the following electromagnetic radiations with correct decreasing order of their associated frequencies from the code given below:

(i) Infra-red radiation

(ii) Microwave radiation

(iii) Ultra-violet radiation

Correct option is B

The correct answer is (b) (iii), (i), (ii)

Explanation:
The electromagnetic spectrum consists of radiations arranged according to frequency or wavelength.

Ultra-violet (UV) radiation has the highest frequency among the three, typically ranging from 8 × 10^14 to 3 × 10^16 Hz.

Infra-red (IR) radiation follows with a lower frequency than UV, ranging from 3 × 10^11 to 4 × 10^14 Hz.

Microwave radiation has the lowest frequency in this set, ranging from 10^9 to 3 × 10^11 Hz.

Frequency is inversely proportional to wavelength; thus, higher frequency means shorter wavelength.

Information Booster:
The full spectrum in decreasing order of frequency is:
Gamma rays > X-rays > UV > Visible > IR > Microwaves > Radio waves

Visible light occupies a very small portion of the spectrum between UV and IR.

Additional Knowledge:

(ii), (iii), (i) (Option a)
Incorrect sequence; places Microwaves (lowest frequency) first.

(iii), (ii), (i) (Option c)
Incorrect sequence; places Microwaves before Infra-red.

(i), (ii), (iii) (Option d)
Incorrect sequence; this is nearly the increasing order of frequency, not decreasing.

So the correct answer is (b)