science mcq only 5 pls give answers only
Answers
Explanation:
(a) True
Sound requires a material medium for travelling. It can travel in solid, liquid and gases. But it can't travel in the vacuum.
(b) False
The number of oscillations per second of a vibrating object is known as its frequency.
The time period is calculated for one oscillation. I.e it is the time taken by a vibrating object to complete one oscillation.
(c) False
The loudness of a sound is proportional to the square of the amplitude of its vibration.
When the amplitude of vibration of a sound is large, the sound is very loud. The sound is feeble for small amplitude.
(d) True
Humans cannot hear sounds of all frequencies. Humans can hear a sound whose frequency falls in the range of 20 Hz−20,000 Hz. The sound having frequency out of this range is inaudible to humans.
(e) False
The pitch of a sound is proportional to its frequency. As the frequency of vibration increases, the pitch of the sound also increases and vice-versa. A sound is said to be high pitched if its frequency of vibration is high, and is low pitched for a small frequency of vibration.
(f) False
Unwanted or unpleasant sounds are known as noise. Sounds that are melodious and pleasing to ear are known as music.
(g) True
Unwanted or unpleasant sounds are known as noise. If one is subjected to loud unpleasant sound continuously for a long time, then it may cause temporary hearing impairment.
Answer:
35) noise
36) Anopheles mosquito
37) plasmodium
38) virus
39) I don't know