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How do you calculate the frequency of red light?

Answer 1

Tricky, what we can state is that it is related to wavelength (normally quoted in the question) by the speed of light (given in the data sheet for exams.)

The wave equation can be used to find the answer if we take these two values: most people "see" orange below 620 nm, and most humans cannot see light above about 750 nm.

#v = f xx lambda# (where the funny symbol, #lambda# means wavelenth in metres)

So #f = v/lambda#

#f_max = (3xx10^8)/(620xx10^-9) = 4.84xx10^14# Hz

#f_min = (3xx10^8]/(750xx10^-9) = 4xx10^14# Hz

So we can say the frequency lies between #4# and #4.84xx10^14# Hertz i.e. an extremely narrow range, showing just what a marvellously precise evolutionary structure the human eye is.

Not too horrible, is it?

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Answer 2

Owen Atkinson

The frequency of red light can be calculated using the formula:

[ \text{Frequency} = \frac{\text{Speed of Light}}{\text{Wavelength}} ]

where the speed of light is approximately (3 \times 10^8) meters per second.

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Answer from HIX Tutor

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.