When one celestial body moves into the path of another, blocking its light, the event is known as an eclipse. There are two types of eclipses. A solar eclipse is when the moon
blocks the sun. A lunar eclipse is when the Earth blocks the sun's light from reaching the
moon. Because objects in space travel according to a pattern, solar and lunar eclipses are
predictable. So you can find out when the next eclipse is happening and whether you can see
if from where you live.
Which of the following is not true about eclipses?
A
they occur when light is blocked
B
they are unpredictable events
they can be lunar or solar
D
they can be seen from Earth

electromagnetic shielding is the practice of reducing the electromagnetic field in a space by blocking the field with barriers made of conductive or magnetic materials. shielding is typically applied to enclosures to isolate electrical devices from their surroundings, and to cables to isolate wires from the environment through which the cable runs. electromagnetic shielding that blocks radio frequency electromagnetic radiation is also known as rf shielding.

the shielding can reduce the coupling of radio waves, electromagnetic fields and electrostatic fields. a conductive enclosure used to block electrostatic fields is also known as a faraday cage. the amount of reduction depends very much upon the material used, its thickness, the size of the shielded volume and the frequency of the fields of interest and the size, shape and orientation of apertures in a shield to an incident electromagnetic

from wikipedia