Two identical springs, each of spring constant K, are connected first series and then in parallel. A mass M is suspended from them. The ratio of the frequencies of vertical oscillations will be :

Options

A. `2:1`
B. `1:1`
C. `1:4`
D. `1:2`

Answer

D

Explanation

Time period of spring mass system is
`" "T=2pisqrt(m/k)`
When connected in series `k.=k/2`
When connected in parallel `k..=2k`
`therefore" "(T.)/(T..)=sqrt(k/(2(2k)))=1/2`