Answer:

Explanation:
Given that,
Charge, Q = 2.1 C
The radius of sphere, r = 1.3 cm = 0.013 m
We need to find the charge per unit volume for this situation. It can be calculated a follows:

So, the charge per unit volume is
.
Mirrors don't cause refraction.
A convex mirror could cause parallel rays to REFLECT away from each other.
Answer:
<h2>2 kg</h2>
Explanation:
The mass of the object can be found by using the formula

f is the force
a is the acceleration
From the question we have

We have the final answer as
<h3>2 kg</h3>
Hope this helps you
The correct option is D.
The model developed by Ptolemy has a lot of inconsistency and during the middle age additional explanation was offered for the claims made by the model. The model was very complicated because it was based on erroneous assumptions.
Copernicus model was simpler and some of his claims were correct.<span />