If each resistance in the figure is of `9Omega` then reading of ammeter is

Options

A. `sqrt3`
B. `sqrt2`
C. `(1)/(sqrt2)`
D. `(1)/(sqrt3)`

Answer

B

Explanation

By appplying conservation of momentum
`mv_(1) + Mv_(2) = 0 rArr v_(1) = -4v_(2)` …..(i)
By applying conservation of energy
`(1)/(2)mv_(1)^(2) + (1)/(2)Mv_(2)^(2) = mgh rArr (v_(1)^(2))/(2) + 2v_(2)^(2) = 20` ……(ii)
`v_(2) = sqrt2m//s , v_(1) = 4 sqrt2 m//s`.