Options

A. `{:(P,,Q,,R,,S),(1,,3,,2,,4):}`
B. `{:(P,,Q,,R,,S),(1,,2,,4,,3):}`
C. `{:(P,,Q,,R,,S),(2,,4,,3,,1):}`
D. `{:(P,,Q,,R,,S),(4,,2,,3,,1):}`

Answer

B

Explanation

P : The springs are connected in series. `k_(eff) = k//2`.
Q : In lower part, two springs of force constant k each are connected in parallel. So, their effective force constant is k. = 2k. Now two springs of force constant 2k each are in series. So, effective force constant, `k_(eff) = 2k//2 = k`
R : `k_(eff) = 2k xx k//(2k + k) = 2k//3 `
S: `k_(eff) = 2k + 3k = 5k`