ELECTROSTATICS

Question 1

what is electrostatics?

Answer 1

Electrostatics is the branch of physics that deals with the study of charges at rest.

Question 2

What are point charges?

Answer 2

Two charges are said to be point charges if their sizes are smaller as compared to the distance between them

Question 3

What is quantisation of charges?

Answer 3

Q = ne
Where n=1,2,3 …….

Question 4

Minimum charge on an object can be

Answer 4

1.6 x 10^-19 C

Question 5

1 C contains how many electrons

Answer 5

6.25 x 10^18 electrons

Question 6

Columbs Law states that

Answer 6

There is a force of attraction or repulsion between two point charges. This force is directly proportional to the product of magnitude of point charges and inversely proportional to the square of distance between them.

Question 7

Positive columb force is

Answer 7

Repulsive

Question 8

Negative columb force is

Answer 8

Attractive

Question 9

What is inverse square law

Answer 9

F ∝ 1/ r^2

Question 10

K is called

Answer 10

Electrical constant

Question 11

The value of k is

Answer 11

9 x 10^9 Nm^2/ C^2

Question 12

Value for permittivity of free space is

Answer 12

8.85 x 10^-12 C^2/Nm^2

Question 13

ε0 is

Answer 13

The permittivity of free space

Question 14

ε is the

Answer 14

Permittivity of dielectric

Question 15

εr is

Answer 15

Relative permittivity

Question 16

Formula for Columbs Law is

Answer 16

On notes, derive it

Question 17

Columbs Law for dielectric is

Answer 17

On notes, derive it

Question 18

Columbs law for dielectric is ________ than Columbs law for free space

Answer 18

Greater

Question 19

For every dielectric, εr is greater than

Answer 19

1

Question 20

For polar materials, relative permittivity is

Answer 20

Infinite

Question 21

Vectorial form of Columbs law

Answer 21

On notes, derive it

Question 22

Write the three forms of force vectors

Answer 22

On notes, derive it

Question 23

Columb force is maximum for _______ magnitude of charges and _________ distance between charges

Answer 23

Maximum, minimum

Question 24

Columbs force is minimum for __________ magnitude of charges and __________ distance between charges

Answer 24

Minimum, maximum

Question 25

When charges are touched/ combined, their magnitude is

Answer 25

Added

Question 26

When charges are separated after combining, their magnitude is

Answer 26

Divided equally between the two

Question 27

What is electric field?

Answer 27

The region or space around a charge in which it exerts force on the other charge.

Question 28

What is electric intensity

Answer 28

The strength of electric field is called electric intensity. It is defined as force acting on a test charge.

Question 29

The SI units of electric intensity are

Answer 29

Newton per columb
Volt per meter

Question 30

The vector form of electric intensity

Answer 30

In notes

Question 31

Electric field is _______ near the charge

Answer 31

Strong

Question 32

Zero field of unlike charges is present

Answer 32

Outside near small charge

Question 33

Zero field of like charges is present

Answer 33

Outside near the smaller charge

Question 34

write the formulas for electric intensity

Answer 34

F/q not
k Q/ r square

Question 35

formula for electric field for hollow charged sphere

Answer 35

zero

Question 36

formula for electric intensity for charged plate

Answer 36

E = σ / 2ε0

Question 37

σ is called

Answer 37

surface charge density

Question 38

σ is equal to

Answer 38

Q/A

Question 39

shortcut for finding electric intensity of oppositely charged plates if E for charged plate is given

Answer 39

multiply by 2

Question 40

electric intensity for two oppositely charged plates is

Answer 40

E = σ / ε0

Question 41

shortcut for finding electric intensity for a charged plate if E for oppositely charged plates is given

Answer 41

divide by 2

Question 42

two charges Q1 and Q2 are exerting force on each other. F/Q2 is the electric intensity of

Answer 42

Q1

Question 42

A charge of 5μC is placed at origin. Its electric intensity at 3i + 4j will be

Answer 42

1080i + 1440j

Question 42

two charges 4μC and 16μC are placed at a distance of 3m. the zero field location from 4μC will be
SOLVE IT

Answer 42

1 m

Question 43

two charges 3μC and -27μC are placed at a distance of 3m. the zero field location from 3μC will be

Answer 43

5 m

Question 44

define electric field lines

Answer 44

the path followed by unit positive charge in an electric field is called electric field

Question 45

the intensity of electric field depends on the __________ of electric field lines

Answer 45

proximity or closeness

Question 46

define electric potential

Answer 46

it is defined as work done on unit positive charge against the electric field

Question 46

formula for potential

Answer 46

V = W/q

Question 47

unit for volt

Answer 47

joule per coulomb

Question 48

base units for volt are

Answer 48

kg m2 s-3 A-1

Question 49

△V

Answer 49

Fd/q

Question 50

formula for potential gradient

Answer 50

E = -△V/△r

Question 50

formula for potential difference if force isn’t given

Answer 50

V = kQ/r

Question 51

what is zero potential point?

Answer 51

there is a point between two opposite charged where total potential is zero. it is called zero potential point.