An unstretched string fixed at both ends resonates at a fundamental frequency of 220 Hz. Which of the following will reduce the fundamental frequency? (a) Double the tension and double the length.
(b) Halve the tension and keep the length and the mass per unit length fixxed.
(c) Keep the tension and the mass per unit length fixed and double the length.
(d) Keep the tension and the mass per unit length fixed and halve the length.

Keep the tension and the mass per unit length fixed and double the length. ( C )

Explanation:

The concept behind the analogy is that of a string fixed at two ends and the fundamental frequency of such spring can be represented using this relation

V =

from this relation above, To reduce the fundamental frequency we will  Keep the tension and the mass per unit length fixed and double the length.

260 miles per hour

explanation:

no simpler subs form complex ones. synthesise = make