Question

An oil – tanker explodes in the sea. At that instant, an aircraft and a submarine were present vertically above and below the oil – tanker respectively at equal distances from it. Find the ratio of the time taken by sound waves to reach them. (Speed of sound in air = 340 m/s. The speed of sound in seawater = 1520 m/s)

• A. 5.40
• B. 4.47
• C. 5.57
• D. 6.40

Answer 1

The correct option is B

4.47

Let the aircraft and the submarine be ‘x’ m above and below the tanker respectively. Time taken by sound to reach the aircraft is $t_{air}=\frac{x}{340}=\frac{x}{340}s$
Time taken by sound to reach the submarine $t_{water}=\frac{x}{1520}=\frac{x}{1520}s$
Ratio of the time taken
$\frac{t_{air}}{t_{water}}=\frac{\left(\frac{x}{340}\right)}{\left(\frac{x}{1520}\right)}=\frac{1520}{340}=4.47$