Calculate the new tension?

A sonometer wire under a tension of N10N, produces a frequency of 250Hz when plucked. Keeping the length of the wire constant, the tension is adjusted to produce a new frequency of 350Hz. Calculate the new tension

A. 39.2N
B. 19.6N
C. 14.2N
D. 7.4N
E. 5.1N

Correct Answer:

Option B = 19.6N