Question

Electromagnetic waves used in a diagnostic tool in medicine have a wavelength range

• A. \(1\ \text{nm}\) to \(10^{-3}\ \text{nm}\)
• B. \(400\ \text{nm}\) to \(1\ \text{nm}\)
• C. \(1\ \text{mm}\) to \(700\ \text{nm}\)
• D. \(0.1\ \text{m}\) to \(1\ \text{mm}\)

Hint:

Remember the sequence of electromagnetic waves: \[ \text{Radio} \rightarrow \text{Microwave} \rightarrow \text{Infrared} \rightarrow \text{Visible} \rightarrow \text{Ultraviolet} \rightarrow \text{X-rays} \rightarrow \gamma\text{-rays} \] Medical diagnosis generally uses X-rays having wavelengths from \[ 1\ \text{nm} \text{ to } 10^{-3}\ \text{nm}. \]

Answer 1

The Correct Option is A

Concept: The electromagnetic waves widely used in medical diagnosis are X-rays. X-rays are highly penetrating electromagnetic waves and are used in:
• Radiography
• CT scans
• Dental imaging
• Bone fracture detection The approximate wavelength range of X-rays is \[ 10^{-9}\ \text{m} \text{ to } 10^{-12}\ \text{m} \] or equivalently, \[ 1\ \text{nm} \text{ to } 10^{-3}\ \text{nm}. \]

Step 1: Identify the electromagnetic wave used for diagnosis.
The term "diagnostic tool in medicine" immediately refers to X-rays because they can penetrate soft tissues but are absorbed more strongly by bones.

Step 2: Recall the wavelength range of X-rays.
\[ \lambda_{X-\text{rays}} = 10^{-9}\text{ m} \text{ to } 10^{-12}\text{ m} \] Converting into nanometres, \[ 1\ \text{nm} \text{ to } 10^{-3}\ \text{nm}. \] Hence, \[ \boxed{1\ \text{nm to }10^{-3}\ \text{nm}} \]