The fringe spacing increases if we use which light

A) Red light

B) Blue light

C) Yellow

D) Green light

To determine which color of light causes an increase in fringe spacing, we need to consider the principles of interference patterns, particularly in the context of a double-slit experiment. The fringe spacing is directly related to the wavelength of the light used. The formula for fringe spacing (Δy) in a double-slit experiment is given by:

Understanding Fringe Spacing

The formula can be expressed as:

Δy = (λL) / d

• Δy = fringe spacing
• λ = wavelength of the light
• L = distance from the slits to the screen
• d = distance between the slits

From this equation, we can see that fringe spacing is directly proportional to the wavelength (λ). This means that as the wavelength increases, the fringe spacing also increases. Conversely, if the wavelength decreases, the fringe spacing will decrease.

Comparing Wavelengths of Different Colors

Now, let's look at the colors of light mentioned in your question:

• Red light - has a longer wavelength (approximately 620-750 nm).
• Blue light - has a shorter wavelength (approximately 450-495 nm).
• Yellow light - has a wavelength between red and green (approximately 570-590 nm).
• Green light - has a wavelength around 495-570 nm.