The speed of sound in a lake is at and at

PHYSICS · Subjective · CBSE · Physics · Waves · Waves

Problem

The speed of sound in a lake is

1470\,\text{m/s}

15^{\circ}\text{C}

and

1530\,\text{m/s}

25^{\circ}\text{C}

. An ultrasonic echo from the lake bed is received

4.0\,\text{s}

after emission at

15^{\circ}\text{C}

. Keeping the depth unchanged, find the total time that will elapse between emission and reception of the echo at

25^{\circ}\text{C}