NCERT Class 9 Science Chapter 10 Sound Waves: Characteristics and Applications Solutions
NCERT Class 9 Science Chapter 10 Sound Waves: Characteristics and Applications Solutions Think It Over (Page No. 184) 1. Two astronauts are repairing the arm of a space station together during a spacewalk. Can they talk to each other and hear the sounds of metal clanking as they do on the Earth? Answer: No, they cannot directly hear each other or the sounds of metal clanking during a spacewalk. This is because sound is a mechanical wave that requires a material medium (solid, liquid, or gas) to travel. Outer space has a near vacuum, meaning there is almost no medium present. Without a medium, sound waves cannot propagate at all. So instead of speaking directly, astronauts communicate through special communication devices fitted into their spacesuits that transmit sound as electrical signals. 2. How do most bats use sound to locate their prey in the dark at night? Answer: Bats use a technique called echolocation to locate their prey. Most bats emit short bursts of ultrasonic waves (fr...