Question

The portion of electromagnetic spectrum sensitive to human eyes ranges from:

• A. 0.1 \(\times\) 10\(^{-6}\)m to 0.3 \(\times\) 10\(^{-6}\)m
• B. 0.4 \(\times\) 10\(^{-6}\)m to 0.7 \(\times\) 10\(^{-6}\)m
• C. 0.4 \(\times\) 10\(^{-7}\)m to 0.7 \(\times\) 10\(^{-7}\)m
• D. 0.4 \(\times\) 10\(^{-8}\)m to 0.7 \(\times\) 10\(^{-8}\)m

Hint:

The visible spectrum is a tiny part of the full EM spectrum. Remember the range as 0.4-0.7 \(\mu\)m or 400-700 nm. Wavelengths shorter than this are Ultraviolet (UV), and longer ones are Infrared (IR).

Answer 1

The Correct Option is B

Step 1: Identify the part of the electromagnetic (EM) spectrum visible to humans. This portion is known as the visible spectrum. It's the range of wavelengths of light that the human eye can perceive, corresponding to the colors of the rainbow.
Step 2: State the wavelength range of the visible spectrum. The visible spectrum typically ranges from approximately 400 nanometers (nm) for violet light to about 700 nanometers (nm) for red light.
Step 3: Convert this range to meters.
We know that 1 nm = 10\(^{-9}\) m.
- 400 nm = 400 \(\times\) 10\(^{-9}\) m = 0.4 \(\times\) 10\(^{-6}\) m
- 700 nm = 700 \(\times\) 10\(^{-9}\) m = 0.7 \(\times\) 10\(^{-6}\) m
So, the range is from 0.4 \(\times\) 10\(^{-6}\) m to 0.7 \(\times\) 10\(^{-6}\) m. This is also commonly written as 0.4 to 0.7 micrometers (\(\mu\)m).