Science 8 Lesson

30. 1 6 The speed of sound depends on ________________.
A.) the pitch of the sound C.) the loudness of the sound
B.) the source of the sound D.) the properties of the medium it travels through
2 18 This is known as the frequency of a sound as perceived by human ear.
A.) Loudness B.) Pitch C.) Vibration D.) Sound wave
3 32 Whenever you will sing inside the bathroom, your voice echoes back to you. Why do you think this happens?
A.) The hard walls or surfaces and the small dimension of the bathroom typically create an aurally pleasing
acoustic environment with many echoes and reverberations contributing to the fullness and depth of voice.
B.)The hard wall surfaces of the bathroom usually made of wood or tiles brings about multiple reflection of sound.
C.) The sound of your voice travels back to you as if it was bouncing on the walls of the bathroom.
D.) Someone may have learned how to imitate your voice and scare you while inside the bathroom.
4 33 What do the pictures show?
A.) During the day, sound waves are refracted upwards and may not reach the observer. At night, sound waves
are refracted downwards and thus, easily reach the observer.
B.) During the day, sound waves are reflected downwards and may not reach the observer. At night, sound waves
are reflected upwards and thus, easily reach the observer.
C.) During the day, sound waves are refracted upwards and may reach the observer. At night, sound waves
are reflected downwards and thus, not easily reach the observer.
D.) None of the above
5 48 Assume that speed of sound in air is about 344 m/s and there is no measurable time delay for light. How far
away is a storm if you note a 4-second delay between a lightning flash and the thunderclap?
A.) 340 m B.) 86 m C.) 1376 m D.) 22.9 m
6 49 If you are 600 meters from a batter when you see him hit a ball, how long will you wait to hear the sound of
the bat hitting the ball (at 20◦C)?
A.) 1.74 s B.) 2 s C.) 2.74 s D. 1 s

31. 1.D
2.B
3.B
4.A
5.C