Question

An important news announcement is transmitted by radio waves to people sitting next to their radios 42 km from the station and by sound waves to people sitting across the newsroom 9.26 m from the newscaster. Taking the speed of sound in air to be 343 m/s, who receives the news first?

Answer 1

Answer:

news will reach to the listener who are 42 km apart

Explanation:

given,

distance of the radios from the station = 42 Km

speed of the sound in the air = 343 m/s

distance of the people = 9.26 m

$time =\dfrac{distance}{speed}$

time taken by the signal to reach to the radio

speed of the electromagnetic wave to reach to the people

speed of electromagnetic wave = 3 × 10⁸ m/s

$t =\dfrac{42000}{3 \times 10^8}$

t = 1.4 μs

time taken to reach to the people

$time =\dfrac{distance}{speed}$

$t =\dfrac{9.26}{343}$

t = 27 ms

time taken by the station to radio is less.

hence, news will reach to the listener who are 42 km apart