How are magnetic poles and electrical charges similar? a. their same forces repel each other, and their opposite forces attract each other. b. their same forces attract each other, and their opposite forces repel each other. c. magnetic force is equal to electric force. d. only electric charges are moving. e. magnetic poles can switch positions.

The correct answer is "Their same forces repel each other, and their opposite forces attract each other".

Explanation:

Magnet has two poles: South pole and North pole.

There is magnetic force of repulsion between the same poles as the same poles repel each other. There is magnetic force of attraction between the opposite poles as the opposite poles attract each other.

The charges can be negative and positive.

There is electrostatic force of repulsion between the same charges as the same charges repel each other. There is electrostatic force of attraction between the opposite charges as the opposite charges attract each other.

Therefore, the correct option is (A).

where is the photo and the answer choices?

speed of light in vacuum is 300,000 km/s

speed of light in other mediums is given by the expression v = c/n, where c is the speed of light in vacuum and n is the refractive index of medium.

for the first medium v = 200,000 km/s

  so, refractive index of medium = 300000/200000 = 1.5

    1.5 refractive index is usually for glass. so first medium is glass.

for the second medium v = 250,00 km/s

so, refractive index of medium = 300000/250000 = 1.2

    1.2 refractive index is usually for water. so second medium is water.

for the third medium v = 0 km/s

so, refractive index of medium = 300000/0 = ∞

    ∞ refractive index is usually for opaque mediums. so third medium is opaque medium.