A material in which electrons are tightly bound and cannot move freely at room temperature is called
Insulators are those materials in which electron are tightly bound and cannot move freely at room temperature.
According to the principle of conservation of charge, in closed system
The law of conservation of charge states that electric charge can neither be created nor destroyed. In a closed system, the amount of charge remains the same. When something changes its charge it doesn't create charge but transfers it.
A coulomb is same as:
Current = charge/time
Therefore charge = current. time (unit of current = ampere,unit of time=second) so, charge = ampere.second
When a glass rod is rubbed with silk, it becomes positively charged because
The charges of glass rod became +ne and of silk cloth became -ne . But total charge of system of rod and cloth remain zero
A hemisphere is uniformly charged positively. The electric field at a point on a diameter away from the centre is directed
When the point is on the diameter and away from the centre of hemisphere which is charged uniformly and positively, the component of electric field intensity parallel to the diameter cancel out. So the electric field is perpendicular to the diameter.
If mica and woolen cloth are rubbed together, then mica gets
Woolen cloth has +ve charge and when mica is rubbed on it , mica gets +vely charged due to (conduction) - flow of charge from wool to mica
Choose the correct statement
The theoretical reason for making the conclusion that the total charge of the universe is constant is the Law of Conservation of Charge. Because of certain symmetries in the structure of the universe, the total electric charge of an isolated system is always conserved. This means that the total charge of an isolated system is the same at all points in time.
To make an uncharged object to have a negative charge we must:
To make an uncharged object have a negative charge we must increase charge on particle and this can be done only by adding electrons to particle.
When conductors are placed in an electric field, their electrons are moved
A substance is said to be conductor if it conduct the electricity .In case of a conductor , the electrons are move in the opposite direction of current ,so it is able to conduct .
Quarks are entities that have
A negative ion is an atom that ________ electrons
negative ion (anion) is a species having excess of electrons than the number of protons.
When a hard rubber rod is given a negative charge by rubbing it with wool:
When a hard rubber rod is given a negative charge by rubbing it with wool, negative charges are transferred from wool to rod.
The value of charge on a body which carries 30 excess electrons is
Here, n = 30 q = ?
e = -1.6 x 10-19 C
So, q = n ∗ e = 30 (1.6 x 10-19 C)
q = -4.8 ∗ 10-18 C
The total negative charge in 1 mol of helium (atomic number 2, atomic mass 4) is:
He atom has 2 electrons. so 1 mole of He has 2*N(N is Avohadro's no.) electrons. then total -ve charge in 1 mole He gas is 2*N*charge of 1 electron. calculating we will get about 1.9*10^5 C.
When we rub a glass rod with silk, then
when glass rod is rubbed with silk electrons are transferred from glass to silk, therefore the mass of glass rod decreases
How many electrons are present in 1 coulomb of charge?
According to Quantisation of Charge we know that,
Q = ne
therefore , 1 coloumb of Charge = n . 1.6*10-19
=>1/ 1.6*10-19 = n
6.25*1018 = n
What does q1 + q2 = 0 signify?
If we have two bodies with charge q1 and q2 on them and we are given q1 + q2 = 0. It means the net charge on the system is zero.
This is possible only if q1 and q2 are equal and opposite.
That is, q1 = +q and q2 = -q or vice versa.
Such that, q1 + q2 = +q + (-q) = 0
A silk cloth rubbed with a glass rod acquire a charge (-1.6 x 10-19) C. Then the charge on the glass rod is
During rubbing ,glass rod acquires + ve charges and silk cloth acquires - ve charges.therefore, the charge on the glass rod is + 1.6×10- 19C
To make uncharged object have a positive charge:
A body consists of atoms which have electrons, protons and neutrons. The electrons have negative charge. The protons are positively charged and the neutrons are neutral. The atom is neutral because the positive and negative charges cancel out each other. On removing electrons , an excess of protons are present and thus the body is said to be positively charged.
Electric charge between two bodies can be produced by
Electric charge between two bodies can be produced by rubbing with each other . The body having lower work function looses electron and becomes positive and the other body gains electrons become negative . Example -- When glass is rubbed with silk , glass becomes positive while silk becomes negative .