# Waves, Sound and Light: Light Waves

## Light Waves: Audio Guided Solution

#### Problem 19:

Jill is helping her younger brother Nathan set up an exhibit for a Science Fair. Nathan’s exhibit pertains to the wave-particle nature of light waves. He wishes to demonstrate the wave nature of light by displaying the two point interference pattern of red laser light (λ = 648 nm). Nathan has purchased a double slit slide from a science warehouse which has slits separated a distance of 0.125 mm. Nathan has asked Jill to determine the slide-to-screen distance which will result in a 2.0 cm separation between adjacent bright spots. What distance will result in this antinodal spacing?

## Habits of an Effective Problem Solver

• Read the problem carefully and develop a mental picture of the physical situation. If necessary, sketch a simple diagram of the physical situation to help you visualize it.
• Identify the known and unknown quantities and record in an organized manner, often times they can be recorded on the diagram itself. Equate given values to the symbols used to represent the corresponding quantity (e.g., v = 3.00x108 m/s, λ = 554 nm, f = ???).
• Use physics formulas and conceptual reasoning to plot a strategy for solving for the unknown quantity.
• Identify the appropriate formula(s) to use.
• Perform substitutions and algebraic manipulations in order to solve for the unknown quantity.