PROBLEM-SOLVING PROTOCOL

1. The operative formula for this work is n l = d sin q
n is an integer that, when multiplied by l, yields the path length difference
l is the wavelength of the wave
d is the distance separating the slits
q is the angular separation between the central maximum and a point on the viewing screen.
if q is less than 10 degrees, then a close approximation is sin q = tan q = X/L where X is the distance on the screen from CM to some point; L is the distance from slits to screen.

1. A TV transmitter broadcasts a signal at 75.MHz A) what is a wavelength of the signal? b) Explain what happens to signal reception when airplane flies close to a house that has a reception antenna on the roof of the building.

2. Two sources are in phase and emit waves of wavelength .68 m. Determine whether constructive or destructive interference occurs at a point where the path length from the two sources are as follows a) 3.4m and 4.08; b) 6.12 m and 5.1 m; c) 2.04 m and 3.74 m

3. Light of wavelength 490 nm falls on a diffraction grating. The third order maximum occurs at an angle of 25 degrees. Find the separation between slits for this grating.

4. When a grating is used with light as a wavelength of 575 nm, a second order maximum is formed an angle of 12.2 degrees. What is a separation of the adjacent lines in this grating?

5. Monochromatic light passes through slits 1.3 mm apart and proceeds to a screen 1.5 m away. The first and second order bright fringes are found to be .5 mm apart. What is the wavelength of the light? what color is the light?

6.The span of wavelengths that comprise the visible spectrum is about 400 nm to 700 nm. If white light passes through two slits .3 mm apart and proceeds to a screen 1.5 m distant, what will be the width of the first order white light spectrum?

7. (Allow me to lead you through this one.)
Destructive interference occurs when the path length difference from two wave sources to some point in space is an odd number of half wavelengths. One can generate an odd number of halves a using the expression (m + ½).for m = 0, 1, 2 … Thus the equation that describes destructive interference is given by (m + ½)l = d sinq. Do not confuse this relationship wit thee equation for constructive interference: ml = dsimq

Consider two speakers 4 wavelengths apart that are in phase to produce a tone whose frequency is 3300 Hz. Consider the speed of sound to be 330 m/s. a) what is the wavelength of the waves emitted by the speakers.

See the diagram below. It shows two speakers and a dashed line 5 m away. WE wish to place chairs on the dashed line so that occupants can hear the speakers.. On one side of the midpoint of the dashed line b) locate the first three points of constructive interference. c) locate the first three points of destructive interference

This page was last reviewed by mgosselin 10/09/2005