Answer:
1. telescope
2.

f- focal length
f- focal length r- the radius of curvature of the mirror

p-the distance of the object from the vertex of the mirror
l-the distance of the figure from the vertex of the mirror
Answer:
The human ear is most sensitive to sounds in the range of 2000 to 3000 Hz
Answer:

Explanation:
Given that,
The speed of an electromagnetic wave traveling in a transparent nonmagnetic substance is given by :

Where
k is the dielectric constant of the substance.
v is the speed of light in water


So, the speed of light in water is 
<u>Answer:</u>
<em>Thunderbird is 995.157 meters behind the Mercedes</em>
<u>Explanation:</u>
It is given that all the cars were moving at a speed of 71 m/s when the driver of Thunderbird decided to take a pit stop and slows down for 250 m. She spent 5 seconds in the pit stop.
Here final velocity 
initial velocity
distance
Distance covered in the slowing down phase = 







The car is in the pit stop for 5s 
After restart it accelerates for 350 m to reach the earlier velocity 71 m/s





total time= 
Distance covered by the Mercedes Benz during this time is given by 
Distance covered by the Thunderbird during this time=
Difference between distance covered by the Mercedes and Thunderbird
= 
Thus the Mercedes is 995.157 m ahead of the Thunderbird.