Two waves interfering at a point have a path difference of lambda / 2. Their corresponding phase difference is exactly: MCQ with Answer and Explanation
Two waves interfering at a point have a path difference of lambda / 2. Their corresponding phase difference is exactly:
A. pi / 2 radians
B. pi / 4 radians
C. 2pi radians
D. pi radians
Answer: Option D
Solution (By JKExamLibrary)
The relationship between phase difference (phi) and path difference (delta x) is given by the formula phi = (2pi / lambda) * delta x. Given a path difference of lambda / 2, substitute this into the formula: phi = (2pi / lambda) * (lambda / 2) = pi radians. This indicates strictly destructive interference.
Explanation:
At maximum height, final velocity v = 0. Using v = u - gt (taking upward positive), 0 = u - gt ⇒ t = u/g. This is time of ascent. Total time of flight would be 2u/g. The equation derives from Newton's first equation of motion under constant acceleration g downward. Memory aid: Time to peak = initial velocity / gravitational acceleration. This fundamental result appears in projectile motion problems. Competitive exams often combine this with energy conservation or symmetry concepts for advanced questions.
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