The speed v of a transverse wave on a stretched wire is given by the expression v ∝ √T where T is the tension in the wire.

A length of wire is stretched between two fixed point. The tension in the wire is T. The wire is gently plucked from the middle. A stationary wave, of fundamental frequency 210 Hz, is produced.

The tension in the wire is now increased to 1.4T. The percentage uncertainty in new tension is 8.0%. The length of the wire is unchanged.

Calculate the new value for the fundamental frequency when the wire is plucked in the middle. Your answer must include the absolute uncertainty written to an appropriate number of significant figures.