20 this is the sum hope this help
Radio waves are radiated by charged particles when they are accelerated. They are produced artificially by time-varying electric currents, consisting of electrons flowing back and forth in a specially-shaped metal conductor called an antenna. ... Radio waves are received by another antenna attached to a radio receiver.
Answer:
It has poor tensile strength despite having high compressive strength
Explanation:
Concrete exhibits high compressive strength when used. However, it has very low compressive strength. This is the reason why concrete is normally combined with steel to make a composite building material called reinforced concrete. The steel reinforces concrete hence increasing the tensile strength in RC buildings. The end composite is durable and fireproof. Generally, the main reason why concrete is not use on its own is due to its poor tensile strength.
