Question

The correct order of electromagnetic waves with increasing frequency is

• A. Infrared, x-rays, gamma rays
• B. Gamma rays, visible light, x-rays
• C. Visible light, infrared, ultraviolet
• D. Visible light, ultraviolet, infrared

Hint:

Frequency increases across the electromagnetic spectrum as: \[ \text{Radio} \rightarrow \text{Microwave} \rightarrow \text{Infrared} \rightarrow \text{Visible} \rightarrow \text{Ultraviolet} \rightarrow \text{X-rays} \rightarrow \text{Gamma rays} \]

Answer 1

The Correct Option is A

Step 1: Recall that frequency and wavelength are inversely related.
For any electromagnetic wave: $c = f\lambda$, so higher frequency means shorter wavelength. Remembering the spectrum in order of wavelength (long to short) is equivalent to remembering it in order of frequency (low to high).

Step 2: List the EM spectrum in order of increasing frequency.
From lowest to highest frequency (longest to shortest wavelength):
Radio waves, Microwaves, Infrared, Visible light, Ultraviolet, X-rays, Gamma rays.

Step 3: Check option 1 (Infrared, X-rays, Gamma rays).
This sequence goes from lower to higher frequency: Infrared is below visible, X-rays are above UV, Gamma rays are the highest. This is a valid increasing order.

Step 4: Check option 2 (Gamma rays, Visible light, X-rays).
Gamma rays have higher frequency than X-rays, but X-rays also have higher frequency than visible light. The order Gamma, visible, X-rays is decreasing then jumping - not consistently increasing.

Step 5: Check options 3 and 4 (involving visible, infrared, ultraviolet).
Infrared has lower frequency than visible light; ultraviolet has higher frequency than visible light. So the order visible, infrared, ultraviolet is not increasing frequency. Similarly for option 4.

Step 6: State the answer.
\[ \boxed{\text{Infrared, X-rays, Gamma rays}} \]