Answer:
Refractive Index = 1.52
Explanation:
As we know speed of light in vaccum is 3 x 10^8 meters per second and distance tavelled by light is 3.97 km or 397000m.
Time taken by light in vaccum = distance / speed = 397000 / 3 x 10^8 = 1.323 x 10^-3 s
Speed of light in liquid = distance / time taken = 261000 / 1.323 x 10^-3 = 197278911 ms^-1 = 1.972 x 10^ 8 ms^-1
According to Snell's law
Refractive index = speed of light in vaccum / speed of light in medium = 3 x 10^8 ms^-1 / 1.972 x 10^8 ms^-1 = 1.52
Answer:
6.18 um
Explanation:
The plumb line will be pulled down by a combination of the gravitationall pull of Earth and of the mountain. The Earth pulls down and the mountain to the side. Because of this it will fall not in a straight line down, but slightly to the side. Since the plumb line will follow the compound gravity we can imagine a rectangle triangle formed by the plumb line, a vertical line that ends at the same height as the plumb line, and the sideways displacement.
The total gravity will be proportional to the plumb line lenght, the vertical line will be proportional to Earth's gravity and the sideways displacement to the mountain pull.
The gravity of Earth is 9.81 m/s^2
The pull of the mountain will be defined by Newton's law of universal gravitation:

Where
F: pull force
G: universal gravitational constant (6.67e-11 m^3/(kg * s)
m1: mass of the mountain
m2: mass of the plumb
r: distance between mountain and plumb (3 km in this case)
If we divide both sides by m2 we obtain the acceleration towards the mountain of the plumb

Now we need the mass of the mountain. This will be its volume times it's density. The volume depends on the radius (since we consider it as a sphere)


So, the acceleration on the plumb will be

This is very small compared to the pull of Earth, so we can make an approximation that the length of the plumb line is equal to vertical line.
We can use the principle of similar triangles to say that:

So:

1. Coulomb's Law
Coulomb's law states that the force of a charged object on another charged object is directly proportional to the product of their charge(s) and inversely proportional to the square of the distance between them.

<em>k</em> is a constant.
2. The Force Would Decrease.
Coulomb's law predicts the electric force between two charged objects in a medium.

where K is the medium's dielectric constant.
Vacuum: 
Plastic: 
Therefore, the force between the two balls will decrease when the plastic sheet is inserted.
3. The Junction Rule states that the sum of magnitudes of the currents directed into a junction equals the sum of the magnitudes of the currents directed out of the current.
4. A Toroid is a doughnut shaped object whose surface is a torus. It annular shape is generated by revolving a circle around an axis external to the circle. Some example uses are RF chokes which is an inductor to have a high impedance to RF current and low impedance to DC current. Another use is variable-frequency oscillator (VFO). The frequency is set by a tuned circuit using capacitors and inductors. The frequency can be changed by adjusting the components in the tuned circuit. Just one last example is in mixers. These are used in transformers for Diode Ring Mixers. Which result in being ready, built, and homebrew.