Question

Find the range of frequency of light that is visible to an average human being 400 nm <λ<700 nm.

Answer 1

Hello!!

$\huge\mathfrak\blue{Answer}$

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Solution:

Given that, 400 m < λ < 700 nm. 1/700nm < 1/ λ < 1/400nm

⇒ 1/7 * 10^-7 < 1/ λ < 1/4 * 10^-7

⇒ 3 × 10^8/7 × 10^-7 < c/λ < 3 × 10^8/7 × 10^-7

(Where, c = speed of light = 3 ×10^8 m/s)

⇒ 4.3 × 10^14 < c/λ < 7.5 ×10^14

⇒ 4.3 × 10^14 Hz < f < 7.5 ×10^14 Hz.

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Thanks!!

Answer 2

Sol.

Given that,

400 m < λ < 700 nm.

1/700nm < 1/ λ < 1/400nm

⇒ 1/7 * 10^-7 < 1/ λ < 1/4 * 10^-7

⇒ 3 * 10^8/7 * 10^-7 < c/λ < 3 * 10^8/7 * 10^-7 (Where, c = speed of light = 3 * 10^8 m/s)

⇒ 4.3 * 10^14 < c/λ < 7.5 * 10^14

⇒ 4.3 * 10^14 Hz < f < 7.5 * 10^14 Hz.