Question

The wavelengths used in various electronic distance measurement systems cover fairly the spectrum of range

• A. 40 m to 450 m
• B. 40 m to 450 mm
• C. 40 m to 450 $\mu$m
• D. 40 m to 450 nm

Hint:

EDM devices span from long-wavelength microwaves to short-wavelength visible light—ranging from 40 m to 450 nm.

Answer 1

The Correct Option is D

The question pertains to the range of wavelengths used in electronic distance measurement systems. These systems utilize electromagnetic waves of different wavelengths to determine distances. The key to solving this question is understanding the electromagnetic spectrum and its associated wavelengths.

In the electromagnetic spectrum, wavelengths are categorized as follows:

• Radio waves: > 1 mm
• Microwaves: 1 mm to 1 m
• Infrared: 700 nm to 1 mm
• Visible light: 400 nm to 700 nm
• Ultraviolet: 10 nm to 400 nm
• X-rays: 0.01 nm to 10 nm
• Gamma rays: < 0.01 nm

Electronic distance measurement systems commonly exploit radio and microwaves due to their ability to travel long distances and penetrate various atmospheric conditions. Additionally, certain applications employ infrared and optical (visible light) techniques.

Given the options, let's analyze their feasibility based on typical usage:

• 40 m to 450 m: Falls within radio and microwave range, commonly used in long-distance communications.
• 40 m to 450 mm: Mostly radio waves, practical but broad for precise measurement.
• 40 m to 450 μm: A range crossing into infrared, not typically used for standard electronic distance measurement.
• 40 m to 450 nm: Spans from radio to visible light, covering techniques from traditional radio wave to optical methods.

Therefore, the correct answer is 40 m to 450 nm, as it encompasses practical and commonly utilized wavelengths across different measurement techniques.