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:
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:
Which of the following methods can be used to charge a metal sphere positively without touching it? Choose the best possible option:
This can be possible by induction, if a negative charge rod is placed near the sphere (at a distance not in touch) than it attracts positive charge inside the sphere towards its side and the negative charges collected on other side and when the surface of sphere connected to earth than the negative charge goes to earth and the sphere remain positively charged.
If mica and woollen cloth are rubbed together, then mica gets:
Woollen 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:
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 a conductor if it conducts electricity. In the case of a conductor, the electrons are move in the opposite direction of the current, so it is able to conduct.
When a negatively charged conductor is connected to earth,
After earthing a positively charged conductor electrons flow from earth to conductor and if a negatively charged conductor is earthed then electrons flows from conductor to earth.
A negative ion is an atom that ________ electrons.
Ions are formed when atoms gain or lose electrons. Gaining electrons changes an atom into a negative ion. Losing electrons changes an atom into a positive ion.
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
► 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:
When we rub a glass rod with silk, then:
How many electrons are present in 1 coulomb of charge?
According to Quantisation of Charge we know that,
Q = ne
Therefore, 1 coulomb of Charge = n * 1.6 * 10-19
⇒ 1/ 1.6 × 10-19 = n
⇒ n = 6.25 × 1018
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.
∴ the charge on the glass rod is + 1.6×10- 19C
To make uncharged object have a positive charge:
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 loses 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.