Answer:
3.0 cm
Explanation:
We can solve this problem by using the mirror equation:

where
f is the focal length of the mirror
p is the distance of the object from the mirror
q is the distance of the image from the mirror
In this problem we have:
f = 1.5 cm is the focal length of the mirror (positive for a concave mirror)
p = 3.0 cm is the distance of the object from the mirror
Therefore, the distance of the image is:

And the positive sign means that the image is real.
(The second part of the exercise is just the description of the image of the first exercise).
Answer:
<u><em>A. wavelength</em></u>
Explanation:
The others are about sound and how high it is. That has nothing to do with time.
Active Optics.
Hope that helps, Good luck! (:
We have the equation for electric field E = kQ/
Where k is a constant, Q is the charge of source and d is the distance from center.
In this case E is inversely proportional to 
So, 
= 485 N/C
= 0.208 cm
= 0.620 cm
= ?

= 
= 53.20 N/C