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:
So, given the eqn Fg=G(m1+m2/r^2) where G is the gravitational constant, m is the mass of the satellite and m2 is the mass of the earth and r is the distance from earth to the satellite, the force of earths gravity should be quartered.
Cause (2r)^2 gets turned into (4r^2) where 4r^2 is compared to r^2
Explanation:
I think the first question is talking about the ionic compound Sodium sulfide and it’s formula is Na2S.
And for the second question, i’m pretty sure it’d be a positive charge
Answer with Explanation:
We are given that
Diameter of fighter plane=2.3 m
Radius=
a.We have to find the angular velocity in radians per second if it spins=1200 rev/min
Frequency=
1 minute=60 seconds
Angular velocity=
Angular velocity=
b.We have to find the linear speed of its tip at this angular velocity if the plane is stationary on the tarmac.

c.Centripetal acceleration=
Centripetal acceleration==
Answer: 5billion years
Explanation: The sun produces energy through radioactive fusion reaction.
Nebula theory states that the gaseous particles of the Earth collapsed as a result of its own gravity which continuously lead to fusion reaction for the production of nuclear energy.
The Core of the Sun is that area up to 25% from the radius of the sun,here the pressure here range up to 250million atmosphere containing mainly hydrogen which gets converted in Helium molecule. The core is the center for energy production accounting for more than 98%, nuclear energy is transmitted at about 4.3million metric tons per second.