A wave of amplitude 10cm travelling on a string is reflected from denser string. Energy of transmitted wave is 64% of the incident wave. Amplitude of reflected wave is
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A wave of amplitude 10cm travelling on a string is reflected from denser string. Energy of transmitted wave is 64% of the incident wave. Amplitude of reflected wave is

G1 Physics · Accepted Answer

Step 1: Use superposition at the boundary. Reflection from a denser/fixed boundary introduces phase reversal; from a free boundary it does not. Step 2: Energy ratio gives amplitude ratio through I ∝ A² for waves in the same medium. Step 3: Combine incident, reflected and transmitted waves with the proper direction. Final: A: 6 cm.