# What spacing lets you see the entire visible spectrum through second order?

## Question:

What spacing lets you see the entire visible spectrum through second order?

## Double slit diffraction:

When light passes through a double slit, the diffraction patterns that appear will be different from that of a single slit diffraction. The bright fringes that appear from diffraction are a result of constructive interference and can be described by the equation:

{eq}\displaystyle dsin\theta = m\lambda {/eq}

where:

• d is the distance between slits
• m is the order of the diffraction pattern
• {eq}\displaystyle \theta {/eq} is the angle between the slit and the nth-order pattern

{eq}\displaystyle \lambda {/eq} is the wavelength of the incident light

For dark fringes, these are products of destructive interference. The equation is a slightly modified version of the first one:

{eq}\displaystyle dsin\theta = (m+\frac{1}{2})\lambda {/eq}

Since the problem specifies a spacing, this means that this should be a double-slit diffraction problem. In this case, we can use:

{eq}\displaystyle...

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