Question
Physics Question on Oscillations
When an oscillator completes 100 oscillations its amplitude reduced to 31 of initial value. What will be its amplitude, when it completes 200 oscillations?
A
81
B
32
C
61
D
91
Answer
91
Explanation
Solution
For damped oscillation amplitude A=A0e−bt
3A0=A0e−b(100T)⇒e−100bT=31
at t=200T,A=A0e−b(200T)=A0(e−100bT)2
⇒A=A0(31)2
=9A0