Arrange the following in the ascending order of wavelength $$ (\lambda) $$ : (A) Microwaves $$ (\lambda_1) $$(B) Ultraviolet rays $$ (\lambda_2) $$ (C) Infrared rays $$ (\lambda_3) $$ (D) X-rays $$ (\lambda_4) $$ Choose the most appropriate answer from the options given below

We need to arrange the electromagnetic waves in ascending order of wavelength.

Recall the wavelength ranges:

(A) Microwaves $$(\lambda_1)$$: wavelength $$\sim 1 \text{ mm to } 30 \text{ cm}$$

(B) Ultraviolet rays $$(\lambda_2)$$: wavelength $$\sim 10\text{ nm to } 400\text{ nm}$$

(C) Infrared rays $$(\lambda_3)$$: wavelength $$\sim 700\text{ nm to } 1\text{ mm}$$

(D) X-rays $$(\lambda_4)$$: wavelength $$\sim 0.01\text{ nm to } 10\text{ nm}$$

Ascending order of wavelength:

X-rays have the shortest wavelength, followed by UV rays, then infrared rays, and microwaves have the longest.

$$\lambda_4 \text{ (X-rays)} < \lambda_2 \text{ (UV)} < \lambda_3 \text{ (IR)} < \lambda_1 \text{ (Microwaves)}$$

The correct answer is Option D: $$\lambda_4 < \lambda_2 < \lambda_3 < \lambda_1$$.