The apparent change in the frequency of a sound caused by the motion of either The Listener or the source of the sound
C. A mechanical wave generally travels faster in gases than liquids.
A diverging lens is used to permit clear vision of an object placed at infinity. The focal length of the lens is -100 cm.
<h3>What is focal length?</h3>
The focal length is half of the radius of curvature of the focal lens.
By the lens maker formula,
1/f = 1/v +1/u
where, v is the image distance and u is the object distance.
Give, the object is at infinity and the image must form at 100 cm, the the focal length will be
1/f = 1/ -100 + 1/∞
f = -100 cm
The focal length must be -100 cm for the diverging lens.
Learn more about focal length.
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Answer:
Frequency, 
Explanation:
Wavelength of a light wave is 450 nm. It is required to find the frequency of this light wave. The speed of light is given by c. So,
f is the frequency of this light
So, the frequency of this light is 
.
Answer:
3400 m
Explanation:
Both lightning and thunder happen at the same time but one is faster than the other. The distance traveled by a sound can be calculated from its speed such that;
speed = distance/time, hence, distance = speed x time.
<em>For a thunder with 340 m/s speed and 10 seconds away from lightning, the distance between the thunder and the lightning can be calculated as</em>;
distance = 340 m/s x 10 s = 3400 m
