(a) The distance of the image formed by the concave mirror is 19.1 cm.
(b) The image formed is diminished and real.
<h3>
Image distance </h3>
The distance of the image formed by the concave mirror is calculated as follows;
1/f = 1/v + 1/u
1/v = 1/f - 1/u
1/v = 1/15 - 1/70
1/v = 0.05238
v = 1/0.05238
v = 19.1 cm
The image distance is smaller than object distance, thus the image formed is diminished and real.
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Answer:
4m/s
Explanation:
May be different considering how long the pole is and how heavy the firefighter is.
Answer:

Explanation:
Refractive Index: It is a measure to find how fast the light travels through a medium. It is ration of the speed of light in vacuum to speed of light in the medium. Speed of light is not constant and varies depending on the density of the medium.
In vacuum the speed of light is 300000 km/s and is denoted by c. When the light beam enters any medium the speed will decrease. Here it is given that the speed in plastic is v. Thus the refractive index(n) is given as:

It is a dimensionless no.
Because the fossil show layers and those layers show what kind of settlements where left behind at that layer
Answer:
Option D 3.9
Explanation:
First, you need to use the correct equation which is the following:
COP = Q/W
Where:
Q = heat absorbed
W = work done by the pump
COP = coefficient of perfomance
We have all the data, so, all you need to do is replace in the above expression and you shoould get the correct result:
COP = 30 / 7.7
COP = 3.896
This result you can round it to 3.9. option D.