The speed of light is 2.998*10^8 m/s. how long does it take light to travel 40 cm ?

The speed of light is:

The distance that should be covered by the light is:

Therefore, we can calculate the time the light takes to cover this distance by using the basic relationship between space, time and distance:

which corresponds to 1.334 nanoseconds.

second mirror gathers light from a faraway object and reflects it to another mirror. - a.

the answer is the first electromagnet (a). this is because it has more coils around the ferromagnetic material. increasing the number of coils increases the surface area in which the metal interacts with the current in the coil. this enables more atoms in the metal to become aligned hence becoming more magnetized.