800 J since watts is a measurement of joules per second
Two small spheres spaced 20.0 cm apart have equal charge.
How many excess electrons must be present on each sphere if the magnitude of the force of repulsion between them is 4.57 x 10-21 N?
Number of Electrons = ?
The description of the question provided above points out to the famous Big Bang Theory. In addition, this theory is among the most accepted by cosmologists because it fits like a glove to the phenomenon the universe is experiencing right now: it is expanding and distances between celestial bodies are getting farther and farther.
Objects appear to us to have the color that
they reflect (paint) or transmit (jello).
Your question is missing one part as "magnification"
i have completed the missing part below
Answer:
a. 
b. 
Explanation:
For this type of numerical we will use the following formulas
......... Eq1
where,
refractive index of the medium surrounding refracting surface/object
i.e. =
refractive index of the refracting surface/object
i.e. 
distance of object from the vertex of the refracting surface
distance of image from the vertex of the refracting surface
radius of curvature of the refracting surface
........... Eq2
where,
magnification
Convention:
Given:
=
because refraction surface is concave
Required:
a. 
b. 
Solution:
a. putting values in eq1, we get
cm
b. 
