Question

A high school website directs parents to not allow student access to blue laser pointers or allow the students to bring them to school. It includes a video describing the danger inherent in the misuse of all laser pointers particularly the blue laser pointer. Why would they claim that blue laser pointers are more of a concern than red laser pointers? A) Colored light falls into the visible region and the red light has a smaller wavelength and higher energy than blue light. B) The wavelengths and energies differ. The ultraviolet blue light has a larger wavelength and smaller energy compared to infrared. C) Both wavelengths fall into the visible light region but blue light has a smaller wavelength and higher energy than red light. D) These colors have similar wavelengths but the blue laser light has more energy than red laser light making it more dangerous.

Answer 1

Both wavelengths are fall into visible light region but blue light has a smaller wavelength and higher energy than red light.

Answer 2

C) Both wavelengths fall into the visible light region, but blue light has a smaller wavelength and higher energy than red light.

Step-by-step explanation:

The energy (E) of a wave is inversely proportional to its wavelength (λ).

E = (hc)/λ

E₁λ₁ = E₂λ₂ Divide both sides by λ₂

E₂ = E₁ × λ₁/λ₂

Let λ₁ refer to red light and λ₂ refer to blue light.

The wavelength of red light (λ₁ ≈ 800 nm) is greater than that of blue light (λ₂ ≈ 400 nm).

E₂ ≈ E₁ × (800/400)

E₂ ≈ 2E₁

E₂ > E₁

Blue light has more energy than red light.

A) is wrong. Red light has a longer wavelength than blue light.

B) is wrong. The order of wavelengths is IR > Red > Blue >UV. UV light has a shorter wavelength and greater energy than infrared light.

D) is wrong. UV waves are much shorter than UV waves.