Question

The wavelength of X-rays is of the order of

• A. 1 cm
• B. 1 m
• C. 10 micron
• D. 1 Angstrom

Hint:

Place X-rays on the electromagnetic spectrum, between ultraviolet and gamma rays, very short wavelength.

Answer 1

The Correct Option is D

Step 1: The electromagnetic spectrum arranges waves by wavelength, from long radio waves down to very short gamma rays.

Step 2: Radio waves have wavelengths of the order of a metre or more, so option B fits radio waves, not X-rays. Microwaves are of the order of centimetres, close to option A, again not X-rays. Infrared radiation is of the order of a few microns, matching option C, still not X-rays.

Step 3: X-rays lie between ultraviolet light and gamma rays on the spectrum. Their wavelength is roughly \(10^{-10}\) metre, which is exactly one Angstrom. This is why option D is correct.

Step 4: This tiny wavelength matters practically because it is close to the spacing between atoms in a crystal lattice, which also happens to be of the order of an Angstrom, and that is what makes X-ray diffraction studies of crystal structure possible.

Step 5: So the correct answer is 1 Angstrom.