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14. waves and sound — Physics STD 11 Science — Question

Rajasthan BoardEnglish MediumSTD 11 SciencePhysics14. waves and sound1 Mark
MCQ
Two pulses in a stretched string whose centres are initially $8 cm$ apart are moving towards each other as shown in the figure. The speed of each pulse is $2 cm/s$. After $2$ seconds, the total energy of the pulses will be
  • A
    Zero
  • ✓
    Purely kinetic
  • C
    Purely potential
  • D
    Partly kinetic and partly potential
✓

Answer

Correct option: B.
Purely kinetic
b
(b) After $2 sec$ the pulses will overlap completely.

The string becomes straight and therefore does not have any potential energy and its entire energy must be kinetic.

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