Answer:
They appear to recede from our viewpoint.
That is, their emitted spectra are shifted toward the red (red-shift).
The wave-lengths that are received on earth are somewhat longer because of the "Doppler" shift of the receding atoms.
A hummingbird can flutter it's wings about 80 times per second.
4,800 divided by 60=80
Answer:
Direct current.
Explanation:
The electric current is defined as the electric charge flowing per unit time. There are two types of current i.e. direct current and alternating current. The unidirectional flow of current describes the direct current. It is said so because the direct current flows only in one direction. This type of current flows in semiconductors, insulators, conductors etc. It is also known as DC current.
<span>When the attraction of the strong force is weaker than the repulsion of the electrostatic force. </span>