question_answer

The amplitude of a damped oscillator decreases to 0.9 times its original magnitude in 5s. In another 10s it will decrease to \[\alpha \] times its original magnitude, where \[\alpha \] equals:                                            [JEE MAIN 2013]

A)  0.7                  

B)       0.81

C) 0.729           

D)       0.6

Correct Answer: C

Solution :

[c]