Electrostatitcs Charges And Fields

Question 1

What is electrostatics

Answer 1

Deals with the study of forces, fields and potentials arising from static changes

Question 2

What charge is glass rod?

Answer 2

Positive

Question 3

What charge is silk?

Answer 3

Negative

Question 4

Plastic Rod’s Charge is

Answer 4

Negative

Question 5

Animal fur is which charge?

Answer 5

Positive

Question 6

What property did Benjamin Franklin give and what did he name it?

Answer 6

Rubbing objects with one another gives them and invisible property that enables them to attract each other.

Question 7

Charge of electron value

Answer 7

-1.6 x 10^-19 C

Question 8

Charge of proton Value

Answer 8

+1.6 x 10^-19 C

Question 9

1 coulomb is how many electrons

Answer 9

6.25 x 10^18 electrons

Question 10

Properties of electric charge

Answer 10

Additivity of charges
-charges can be added
Quantization of charges
-always integral multiple of electron charge
Conservation of charges
-net charge for an isolated system can neither be created nor destroyed

Question 11

Methods of charging a body

Answer 11

Friction (rubbing)
Conduction (touching)
Induction

Question 12

What happens in conduction

Answer 12

The charge splits q/2 in both bodies.

Question 13

If the distance between charges is increased then the force_____

Answer 13

Is 1/r square of that number of the original

Question 14

Coulomb’s law

Answer 14

F is directly proportional to q1q2
F is directly proportional to 1/r ².
F is directly proportional to q1q2/r ²
F = k|q1q2|
R ²

K= Coulomb’s Constant

Question 15

Value of Coulomb’s constant

Answer 15

K = 9 x 10 ⁹ Nm ² /c ²

Question 16

K is also equal to

Answer 16

1/4 πε0
So F = 1 x q1q2
4πε0 R ²

Question 17

Limitations of Coulomb’s Law

Answer 17

Only when charges are point charges

Only when charges are at rest

Question 18

What is an electric field?

Answer 18

The field surrounding the charged particle in which it can exert an influence on another charged particle

Question 19

What are the types of continuous charge distribution?

Answer 19

Linear charge distribution
surface charge distribution
volume charge distribution

Question 20

Electric field formula

Answer 20

E = f/q0

F = kqQ
r ²
= kqQ x r vector (cap)
q0 r²
= kQ
r ²

Question 21

What is electric dipole?

Answer 21

A pair of equal and opposite point charges q and -q separated by a distance of 2a.
It is defined as a simple product of magnitude of either charge, and the distance of separation between the two charges and its denoted by
vector p = q(2a) pcap

Question 22

What is point diplole?

Answer 22

When the dipole size 2a approaches zero, the charge q approaches infinity in such a way that the product p= q(2a) is finite. Such a dipole is referred as a point dipole.

Question 23

Properties of electric field lines

Answer 23

1. Field lines start from positive charges and end at negative charges. If there is a single charge, they may start or end at infinity.
2. In charge-free region electric fuel lines can be taken to be continuous curves without breaks.
3. Two lines can never cross each other ( if they did the field that the point of intersection will not have a unique direction, which is absurd.)
4. Electrostatic field lines do not form any closed loops. This follows the the conservative nature of electric field.

Question 24

Torque

Answer 24

Is equal an opposite forces act with a separation in their line of action they produce a couple the torque due to its couple is: force times separation between lines of action of force. (Fx2a)

2asintheta = torque
pesintheta = torque
Or in vector form pen= torque

Question 25

Dipole at equatorial plate

Answer 25

-_kp_ = E _p (r ² + a ² ) ^3/2 -_kp_ = E _p r ³

Question 26

Dipole axial plate

Answer 26

_2kp_ r ³

Question 27

Electric flux

Answer 27

The total number of electric field lines passing given area in a unit time is defined as electric flux Δ Φ = EΔS

Question 28

Properties of Gauss’s Law

Answer 28

(i)Gauss's law is true for any closed surface, no matter what its shape or size. (ii) The term q on the right side of Gauss's law, Eq. (1.31), includes thi sum of all charges enclosed by the surface. The charges may be locate anywhere inside the surface. (iii) In the situation when the surface is so chosen that there are som charges inside and some outside, the electric field (whose flux appean on the left side of Eq. (1.31)| is due to all the charges, both inside an outside S. The term q on the right side of Gauss's law, however represents only the total charge inside S. iv) The surface that we choose for the application of Gauss's law is called the Gaussian surface. You may choose any Gaussian surface and apply Gauss's law. However, take care not to let the Gaussian surface pass through any discrete charge. This is because electric feld due to a system of discrete charges is not well defined at the location of any charge. (As you go close to the charge, the field grows without any bound.) However, the Gaussian surface can pass through a continuous charge distribution. Gauss's law is often useful towards a much easier calculation of the electrostatic field when the system has some summetry. This is facilitated by the choice of a suitable Gaussian surface. (v)Finally, Gauss's law is based on the inverse square dependence on distance contained in the Coulomb's law. Any violation of Gauss's law will indicate departure from the inverse square law.

Question 29

Gauss’s law

Answer 29

The total charge enclosed in a closed surface is proportional to the total flux enclosed by the surface therefore, if Φ is total flux and ε₀ is electric constant, the total electric charge Q and closed by the surface is Q = Φ ε₀ Φ = Q/ε₀

Question 30

Superposition principle

Answer 30

superposition principle states that the total force on a charge due to a number of other charges is the vector sum of the individual forces exerted by each charge separately.

Question 31

A negative charge moves in which direction of the electric field

Answer 31

Opposite

Question 32

Value of μ₀

Answer 32

4π * 10⁻⁷ H/m

Question 33

Work done

Answer 33

W = pE (cosθ₁ – cosθ₂)