Two light waves will interfere constructively if the path-length difference between them is a whole number.
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SUPERPOSITION</h3>
The principle of superposition state that, when two or more waves meet at a point, the resultant displacement at that point is equal to the sum of the displacements of the individual waves at that point.
Interference of waves can either be constructive, or destructive.
The two light waves, initially emitted in phase, will interfere constructively with maximum amplitude if the path-length difference between them is a whole number of wavelenght 1λ, 2λ, 3λ, 4λ etc
The equivalent phase differences between the waves will be 2
or 360 degrees, 4
or 720 degrees, 6
1080 degrees etc
Therefore, the two light waves, initially emitted in phase, will interfere constructively with maximum amplitude if the path-length difference between them is a whole number.
Learn more about Interference here: brainly.com/question/25310724
On the change in potential energy
Answer:
The pendulum frequency is (c) the same, or very close to it
Explanation:
The simple pendulum corresponds to a simple harmonic movement, to reach this approximation in the expression of the force the sine of the angle (θ) approaches an angle value, this is only true for small angles, generally less than 15º
Sine (15th) = 0.2588
The angle in radians is 15º π / 180º = 0.26180.2588 / 0.2618
The difference between these two values is less than 1.2%
for smaller angle the difference is reduced more
Therefore, the period for both the 5º and 10º angles is almost the same