When Casey looks at a CD or DVD she notices that there is a rainbow pattern that is created by the light. She became curious and
shone light directly at it and a pattern was created on the wall. What is the cause of this pattern?
2 answers:
Answer:
Interference
Explanation:
A CD is made up of thousands of pits arranged in the form of spiral tracks.These repeated patterns of pits form a thin film.
This film has the thickness of the order of the wavelength of the light which causes the interference of the waves of the light waves. The incident ray of light gets reflected from the top layer of the film partially and then after striking the bottom layer of the film creating a phase difference responsible for the constructive and destructive interference.
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Answer:
v = -1.8t+36
20 seconds
360 m
40 seconds
36 m/s
The object speed will increase when it is coming down from its highest height.
Explanation:
Differentiating with respect to time we get
a) Velocity of the object after t seconds is v = -1.8t+36
At the highest point v will be 0
b) The object will reach the highest point after 20 seconds
c) Highest point the object will reach is 360 m
d) Time taken to strike the ground would be 20+20 = 40 seconds
Acceleration will be taken as positive because the object is going down. Hence, the sign changes. 2 is multiplied because the expression is given in the form of
e) The velocity with which the object strikes the ground will be 36 m/s
f) The speed will increase when the object has gone up and for 20 seconds and falls down for 20 seconds. The object speed will increase when it is coming down from its highest height.
Answer:
Explanation:
Total length of the wire is 29 m.
Let the length of one piece is d and of another piece is 29 - d.
Let d is used to make a square.
And 29 - d is used to make an equilateral triangle.
(a)
Area of square = d²
Area of equilateral triangle = √3(29 - d)²/4
Total area,
Differentiate both sides with respect to d.
For maxima and minima, dA/dt = 0
d = 8.76 m
Differentiate again we get the
(a) So, the area is maximum when the side of square is 29 m
(b) so, the area is minimum when the side of square is 8.76 m