In: Physics
A glass rod is rubbed on a silk cloth, and then separated
from each other. When the rod and the silk cloth are
separated by 35 cm, a force of magnitude 2.20x10^−21 N is
measured between the rod and cloth.
a) Calculate the total charge on the glass rod.
b) Calculate the total charge on the silk cloth.
c) How many electrons were transferred from the glass rod to the
silk cloth.
d) Explain why a material like copper is a good conductor of
electricity, while a material like wood is a poor
conductor of electricity.
a). As the glass rod is rubbed on a silk cloth, assume the Q amount of charge is transferred from glass to silk so:
b) Charge on the silk clothes :
c) Let n electrons are transferred from the glass rod so
d) Cu has an atomic no of 29. So it has unpaired electrons in the outermost shell. These unpaired electrons become free and roam around and these are responsible for the conduction of electricity. We can also explain it in terms of the band theory of metals. In the case of copper conduction and valence band are not too far from each other. So electrons from the valence band can jump to the conduction band and conduct electricity.
In the case of wood, there is a lack of free electrons. So it is bad conductor of electricity.