Acceleration means speeding up, slowing down, or changing direction. The graph doesn't show anything about direction, so we just have to examine it for speeding up or slowing down ... any change of speed.
The y-axis of this graph IS speed. So the height of a point on the line is speed. If the line is going up or down, then speed is changing.
Sections a, c, and d are all going up or down. Section b is the only one where speed is not changing. So we can't be sure about b, because we don't know if the track may be curving ... the graph can't tell us that. But a, c, and d are DEFINITELY showing acceleration.
Answer :
Label A - nucleus.
Label B- electron cloud.
Explanation :
An atom is the smallest unit of a matter that consist of three subatomic particles which are electrons, protons and neutrons.
The protons and the neutrons are located inside the nucleus or the center of the nucleus where the mass of the an atom is concentrated.
The electrons are located around the nucleus.
The protons are positively charged, the electrons are negatively charged and the neutrons are neutral that means it has no charge.
In the picture, label A shows the nucleus.
Electrons has the ability to revolve around the nucleus in a fixed circular orbit. Electron cloud represents the spreading of the electrons energy.
In the picture, label B shows the electron cloud.
Hence, the label A - nucleus and label B- electron cloud.
