As the footnote on above page indicates, the separation, $\Delta x$, between two adjacent bright areas or fringes in the double slit interference pattern is determined by the distance, $a$, between the slits, the distance, $S$, between the plane of the slits and the screen on which the pattern is projected, and the wavelength, $\lambda$, of light used in the experiment. Specifically, the relationship among these variables is given by:

$$\Delta x=\left(\frac{S}{a}\right) \lambda .$$

Based on this equation, for a given slit spacing and screen distance, for which color of light, red or blue, will the fringe spacing be greater? For a given slit spacing and wavelength, if the screen distance, $S$, is increased, what happens to the fringe spacing? If the separation between the slits is decreased, for a given value of $\lambda$ and $S$, how will $\Delta x$ change? Suppose that a beam of red light from a He-Ne laser $(\lambda=633 \mathrm{~nm})$ strikes a screen containing two narrow slits separated by $0.200 \mathrm{~mm}$. The fringe pattern is projected on a white screen located $1.00 \mathrm{~m}$ away. Find the distance in millimeters between adjacent bright areas near the center of the interference pattern that develops. As mentioned in the text, the relationship given above could be used to calculate the wavelength of light in an experiment in which the other three quantities are measured.

What is chromatic aberration? How can it be remediated?

After hitting a ball into a water trap, a golfer looks into the pond and spies the ball within apparent easy reach. Reaching in to retrieve the ball, the golfer is surprised to find that it cannot be grasped even with a fully extended arm. Explain why the golfer was deceived into thinking that the location of the ball was close at hand.

Describe how you could use two large, circular Polaroid filters in front of a circular window as a kind of window shade.

A choreographer uses a number line to position dancers for a ballet. Dancers A and B have coordinates $5$ and $23$, respectively. Find the coordinate for each of the following dancers based on the given locations.

Dancer $E$ stands at a point that divides the line segment from Dancer $A$ to Dancer $B$ in a ratio of $2$ to $1$.

A choreographer uses a number line to position dancers for a ballet. Dancers A and B have coordinates $5$ and $23$, respectively. Find the coordinate for each of the following dancers based on the given locations.

Dancer $F$ stands at a point that divides the line segment from Dancer $A$ to Dancer $B$ in a ratio of $1$ to $5$.

What is different about an image formed with a convex mirror compared to an image formed with a concave mirror? What are the advantages of each type of mirror?

Distinguish between specular reflection and diffuse reflection.

A ray of yellow light crosses the boundary between glass and air, going from the glass into air. If the angle of incidence is $20^{\circ}$, what is the angle of refraction?

What are the three categories used to describe our mental perception of a sound? On what physical properties of sound waves does each depend?

What do you see if you hold out your right hand in front of an aeroplane mirror? (Be cautious now. Describe the image carefully.) If you’re having trouble, place a tube of toothpaste or other object with writing on it in front of the mirror. Now what can you say? (The process you’re witnessing is called inversion and is one of the common characteristics of plane mirrors.)

A person riding on a bus hears the sound from a horn on a car that is stopped. What is different about the sound when the bus is approaching the car compared to when the bus is moving away from the car?

A low-frequency sound is heard and then a high-frequency sound is heard. Which sound has a longer wavelength?

Two plane mirrors are hinged along one edge and set at right angles to one another as shown in Figure mentioned. A light ray enters the system, striking mirror 1 with an angle of incidence of $45^{\circ}$. Draw a diagram showing the direction in which the ray will exit the system. This device is called a corner reflector and is the basis for the design of bicycle reflectors and some highway signs.