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.
Answer:
length
Explanation:
SI unit of volume = m^3
SI unit of area = m^2
volume unit / Area unit = m^3 / m^2
i.e, unit of length
Answer:
c)the gravitational forces of people is so small it is overshadowed by that of earth.
Explanation:
The gravitational force between two objects is given by:

where
G is the gravitational constant
m1 and m2 are the masses of the two objects
r is the distance between the two objects
From the formula, we see that the gravitational force depends on the masses of the objects: since the mass of the Earth (
is much much larger than the average mass of one person (80-100 kg), then the gravitational force exerted by the Earth on a person is also much much larger than the gravitational force between two people.
The value of the c will be (0 i+0 j+0 k). c is a vector that is along the positive x-axis and has the condition a(b+c)=0.
<h3>What is a vector?</h3>
A vector is a quantity or phenomena with magnitude and direction that are independent of one another. The phrase also refers to a quantity's mathematical or geometrical representation.
Given ;
a=3i-2j+k
b=-i-4j+3k
Given property:
a(b+c)=0
-i-4j+3k ((-i-4j+3k)+c)=0
(3+8+3)(-i-4j+3k)c=0
14(-i-4j+3k)c=0
c=0 i+0 j+0 k
Hence, the value of the c will be (0 i+0 j+0 k).
To learn more about the vector refer to the link;
brainly.com/question/13322477
#SPJ1
Answer:
All of the above statements are true.
Explanation:
All matter is composed of atoms of which have subatomic particles. Subatomic particles are electrons, protons and neutrons. Each particle has electric charges.
Electrons have a negative charge, protons have a positive charge and neutrons have zero charge.
Between two nearby charges initially at rest, a type of forces, called electrostatic, is always established in such a way that, if the charged particles are small enough so that they can be considered punctual, the following conditions are met:
-
The force established between the two has a direction that coincides with an imaginary straight line that joins the two charges.
- The force exerted on one load points towards the other when the two have different signs, one positive and the other negative. (attractive force).
- The sense of force is directed to the opposite side of the charge when both have the same sign (repulsive force).