Electric Charge And Fields

Question 1

Conservation of charge?

Answer 1

Total charge of an isolated system is constant

Question 2

Charging by rubbing applies only to ______?

Answer 2

Insulators

Question 3

Charging by conduction VS induction?

Answer 3

Conduction: transfer of e’s via contact with another surface
Induction: Charges uncharged body with opp charged particles

Question 4

Quantization of charge?

Answer 4

All charges are integral multiples of charge of e’ = 1.6/10¹⁹C
Q = ne

Question 5

Coulumb’s Law + formula + charge of K?

Answer 5

Force btw two point charges is directly prop to product of magnitude of the charges & inversely to Sq of distance btw them
Direction is along the line which joins charges
F = k(q1q2)/r²
k = 9 × 10⁹ Nm²/C²

Question 6

Coulomb’s law is applicable only to _____?

Answer 6

Point charges

Question 7

Principle of superposition?

Answer 7

Total force on q1 = vector sum of all forces acting on q1
Fi = k Σ [qi qn/(rni)²] × rni

Question 8

Electric field + formula?

Answer 8

Force per unit charge exerted on a positive test charge at rest at that point
E = F/q

Question 9

Source charge VS test charge

Answer 9

Electric charge that produces the electric field is called a source charge.
Test charge is a small positive charge used to detect the presence of electric field. It should be as small as possible so that it doesn’t affect the electric field due to source charge

Question 10

Relation btw force & electric field?

Answer 10

E= F/q where q is test charge
It is used to calculate electric field strength

Question 11

Electric field lines? Why use them? Direction of them?

Answer 11

A way of pictorially mapping the electric field around a configuration of charge(s).
To show electric fields, magnetic fields.
Tangent on these lines at any point gives the direction of net field at that point.

Question 12

E.F.L properties?

Answer 12

1. Show a continuous curve without having any breakage in a charge-free region
2. Never cross each other
3. Start on the +ve charge and end in the -ve charge
4. Do not form any closed loops

Question 13

Electric field intensity? mathematically?

Answer 13

Force experienced per unit positive test charge placed at that point without disturbing the source charge.
E = F/Q

Question 14

E.F.I due to circular coil formula?

Answer 14

E = KQx/(R²+ x²)³/²

Question 15

Electric dipole?

Answer 15

pair of equal or opposite charges A and -B which are separated by distance 2x

Question 16

9. Electrostatic forces are _______ forces

Answer 16

conservative

Question 17

Electric charge

Answer 17

Fundamental property of any substance that makes it possible to make or exert electrical forces or respond to electrical forces

Question 18

Charge of proton

Answer 18

1.6/10¹⁹C

Question 19

Charge of neutron

Answer 19

0C

Question 20

Properties of electric charge

Answer 20

Additivity
Quantised in nature

Question 21

Is a charge if 5.8/10¹⁸ C possible?

Answer 21

Q = 5.8/10¹⁸
Q=ne
n = 36.02
So not possible

Question 22

E(equator)/2 =

Answer 22

E(axis)

Question 23

Use of Gauss theorem?

Answer 23

Calculation of E.F when system has some symmetry