A wave pulse, travelling on a two -piece string, gets partially reflected and partially transmitted at the junction. The reflected wave is inverted in shape as compared to the incident one. If the incident wave has wavelength λ and the transmitted wave λ
(a) λ` >λ
(b) λ` = λ
(c) λ` < λ
(d) nothing can be said about the relation of λ and λ`.
The correct answer is (c) λ`< λ
EXPLANATION:
Since the reflected wave is inverted, the pulse is traveling from the lighter string to heavier string. Hence the speed of the incident pulse is more than the speed of the transmitted pulse. Let the velocity of the incident pulse = v and the transmitted pulse = v'. The frequency of the pulses will be the same, hence v = νλ and v' = νλ'. Now v > v'
→νλ > νλ'
→λ > λ'
→λ' < λ
Hence option (c).