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:
-320 μJ.
Explanation:
Consider a point with an electrical charge of . Assume that
is the electrical potential at the position of that charge. The electrical potential of that point charge will be equal to:
.
Keep in mind that since both and
might not be positive, the size of the electrical potential energy might not be positive, either.
For this point charge,
; (that's -8.0 microjoules, which equals to
)
.
Hence its electrical potential energy:
.
Why is this value negative? The electrical potential energy of a charge is equal to the work needed to bring that charge from infinitely far away all the way to its current position. Also, negative charges are attracted towards regions of high electrical potential. Bringing this negative charge to the origin will not require any external work. Instead, this process will release 320 μJ of energy. As a result, the electrical potential energy is a negative value.
Answer:
Explanation:
consider the mass of each train car be m
m₁ = m₂ = m₃ = m
speed of the three identical train
u₁ = u₂ = u₃ = 1.8 m/s
m₄ = m u₄ = 4.5 m/s
m₅ = m u₅ = 0 (initial velocity )
final velocity
v₁ = v₂ = v₃ = v₄ = v₅ = v
using conservation of momentum
m₁u₁ + m₂u₂ + m₃u₃ + m₄u₄ + m₅u₅ = m₁v₁ + m₂v₂ + m₃v₃ + m₄v₄ + m₅v₅
m (1.8 + 1.8 + 1.8 +4.5) = 5 m v