Q. The amplitude of a damped oscillator decreases to times its original magnitude is . In another it will decrease to a times its original magnitude, where equals

 3273  188 JEE MainJEE Main 2013Oscillations Report Error

Solution:

Amplitude decreases exponentially. In 5 s it remains 0.9 times. Therefore in total 15 s it will remains (0.9) (0.9) Answer is 4. (0.9) = 0.729 times its original value.