The fundamental frequency of a plucked wire under a tension of 400N is 250Hz. When the frequency is changed to 500 Hz at constant length, the tension is
A
1600N
B
400N
C
160N
D
40N
Verified Correct Answer: A.
Physical Principles & Numerical Solution
The fundamental frequency is related to tension as
F ∝ √T
=>F= K√T
∴F1=F2=>250=500√T1√T2√400√T2
∴√T2 = 500√400 = 2 x 20250
∴ T2 = 402 = 1600N
Source: Myschool Past Questions Archive (Record #14387)