Question

It takes 2 seconds for a sound wave to travel between two fixed points when the day temperature is 10°C. If the temperature rises to 30°C, the sound wave travels between the same fixed parts in __________

(a) 1.9s

(b) 2s

(c) 2.1s

(d) 2.2s

I had been asked this question in final exam.

This intriguing question comes from Progressive Waves in portion Waves of Engineering Physics I

Answer 1

Right answer is (a) 1.9s

The explanation is: v∝√T

t∝1/v

t∝1/√T

t2/t1 = √(T1/T2)=√((273+10)/(273+30))=√(283/303)

t2=√(283/303)×2s=1.9s.