Which statement is true about the part of the electromagnetic spectrum that is divided into seven ranges of wavelengths?

a. it is one of three parts visible to the human eye.
b. it is the only part visible to the human eye.
c. it is one of two parts visible to the human eye.
d. it cannot be seen by the human eye unless it rains.

Alightning strike consists of charge moving from a cloud to the ground . in one particular case, the electrons in a lightning strike are confined to travel within a radius of 1.5 m and to move at a speed of 5.0 x 10 m/s. if the density of electrons in the strike is 10'15 electrons/m what current is carried by the lightning ?

Picture a all traveling at a constant speed around the inside of a circular structure. is the ball accelerating? explain your answer

I'm thinking it's 2 you are asked to explain the earth's magnetic field. which is the best reply? 1. the earth's magnetic south is similar to the north pole of a magnet. 2. the earth's core has a strong magnetic charge similar to the south pole of a magnet. 3. the earth's geomagnetic south is similar to the south pole of a magnet. 4. the earth's magnetic charge is not centered at either pole; it varies based on location.