The correct option (B) 12
Explanation:
T = 2π √(ℓ/g)
hence T1 = 2π √{(144)/g} & T2 = 2π √{(121)/g}
∴ (T1/T2) = √{(144)/(121)} = (12/11) i.e. T1 > T2
∴ when shorts pendulum completes n oscillations, the lunges one
completes n – 1 oscillation (when in same same)
∴ n T2 = (n – 1)T1
∴ (T2/T1) = {(n – 1)/n}
∴ (11/12) = 1 – (1/n)
∴ (1/n) = 1 – (11/12) = (1/12)
n = 12