Electrostatics

Question 1

What is the unit of electric charge?

Answer 1

Coulomb (C)

Question 2

True or False: Like charges repel while opposite charges attract.

Answer 2

True

Question 3

What law describes the force between two point charges?

Answer 3

Coulomb’s Law

Question 4

Fill in the blank: Coulomb’s Law states that the force between two charges is directly proportional to the product of the magnitudes of the charges and inversely proportional to the square of the _____ between them.

Answer 4

distance

Question 5

What is the formula for Coulomb’s Law?

Answer 5

F = k * |q1 * q2| / r^2

Question 6

In Coulomb’s Law, what does ‘k’ represent?

Answer 6

Coulomb’s constant

Question 7

What is the approximate value of Coulomb’s constant (k)?

Answer 7

8.99 x 10^9 N m²/C²

Question 8

Define electric field.

Answer 8

The electric field is a field around a charged object that exerts a force on other charged objects.

Question 9

What is the unit of electric field strength?

Answer 9

Newton per Coulomb (N/C)

Question 10

True or False: The direction of the electric field is defined as the direction a positive test charge would move.

Answer 10

True

Question 11

What is the formula to calculate the electric field (E) due to a point charge?

Answer 11

E = k * |q| / r^2

Question 12

What does the symbol ‘q’ represent in the electric field formula?

Answer 12

The charge creating the electric field

Question 13

Fill in the blank: The electric potential energy (U) between two charges is given by the formula U = k * _____ / r.

Answer 13

q1 * q2

Question 14

What is the unit of electric potential energy?

Answer 14

Joule (J)

Question 15

True or False: Electric potential energy can be negative.

Answer 15

True

Question 16

What is the relationship between electric potential (V) and electric potential energy (U)?

Answer 16

V = U/q

Question 17

What is the unit of electric potential?

Answer 17

Volt (V)

Question 18

True or False: 1 Volt is equal to 1 Joule per Coulomb.

Answer 18

True

Question 19

What does it mean if the electric potential at a point is zero?

Answer 19

It means that a test charge would have zero potential energy at that point.

Question 20

Fill in the blank: The work done (W) in moving a charge in an electric field is equal to the change in _____ energy.

Answer 20

potential

Question 21

What is the concept of equipotential surfaces?

Answer 21

Equipotential surfaces are surfaces where the electric potential is the same at every point.

Question 22

True or False: No work is done when moving a charge along an equipotential surface.

Answer 22

True

Question 23

What is the principle of superposition in the context of electric fields?

Answer 23

The total electric field is the vector sum of the electric fields due to individual charges.

Question 24

What is the formula for the electric field due to multiple point charges?

Answer 24

E_total = E1 + E2 + E3 + … + En

Question 25

Fill in the blank: The force on a charge in an electric field is given by the equation F = qE, where F is _____, q is charge, and E is electric field strength.

Answer 25

force

Question 26

What is the electric field inside a conductor in electrostatic equilibrium?

Answer 26

Zero

Question 27

True or False: The electric field lines point away from positive charges and towards negative charges.

Answer 27

True

Question 28

What is the significance of the density of electric field lines?

Answer 28

The density of electric field lines represents the strength of the electric field.

Question 29

What is the formula for dipole moment (p)?

Answer 29

p = q * d

Question 30

What does 'd' represent in the dipole moment formula?

Answer 30

The distance between the charges

Question 31

True or False: A dipole experiences a torque in a uniform electric field.

Answer 31

True

Question 32

What is the formula for the torque (τ) on a dipole in an electric field?

Answer 32

τ = pE sin(θ)

Question 33

What does θ represent in the torque formula for a dipole?

Answer 33

The angle between the dipole moment and the electric field direction

Question 34

Fill in the blank: The potential energy of a dipole in an electric field is given by U = -pE cos(θ), where p is the dipole moment and E is the _____ field strength.

Answer 34

electric

Question 35

What is the electric field produced by an infinite plane sheet of charge?

Answer 35

E = σ / (2ε₀)

Question 36

What does σ represent in the electric field formula for a plane sheet?

Answer 36

Surface charge density

Question 37

What does ε₀ represent?

Answer 37

The permittivity of free space

Question 38

True or False: Electric fields can do work on charged particles.

Answer 38

True

Question 39

What is the relationship between electric field and force on a charge?

Answer 39

The force on a charge is equal to the charge multiplied by the electric field (F = qE).

Question 40

Define 'electrostatic shielding'.

Answer 40

Electrostatic shielding is the phenomenon where a conductor can block the effects of an external electric field.

Question 41

What is the effect of distance on the electric force between two charges?

Answer 41

The electric force decreases with the square of the distance between the charges.

Question 42

Fill in the blank: The principle of conservation of energy states that energy cannot be _____ or destroyed, only transformed.

Answer 42

created

Question 43

What is the work-energy theorem in the context of electrostatics?

Answer 43

The work done on a charge is equal to the change in its electric potential energy.

Question 44

True or False: Electric potential energy is scalar, while electric force is vector.

Answer 44

True

Question 45

What is the effect of a charged conductor on the electric field inside it?

Answer 45

The electric field inside a charged conductor is zero.

Question 46

What is the electric field at a point due to a uniformly charged ring at its center?

Answer 46

Zero

Question 47

Fill in the blank: The energy stored in an electric field is called _____ energy.

Answer 47

electrostatic

Question 48

What is the formula for electrostatic potential energy stored in a capacitor?

Answer 48

U = 1/2 CV²

Question 49

What does C represent in the capacitor energy formula?

Answer 49

Capacitance

Question 50

True or False: Capacitance is defined as the ability of a system to store charge per unit voltage.

Answer 50

True

Question 51

What is the relationship between electric potential and distance for a point charge?

Answer 51

Electric potential decreases with increasing distance from the charge.

Question 52

Define 'polarization' in the context of electric fields.

Answer 52

Polarization is the alignment of dipoles in a material in response to an external electric field.

Question 53

What is an insulator?

Answer 53

A material that does not allow electric charge to flow through it easily.

Question 54

What is a conductor?

Answer 54

A material that allows electric charge to flow through it easily.

Question 55

True or False: Metals are generally good conductors of electricity.

Answer 55

True

Question 56

Fill in the blank: Rubber is an example of a __________.

Answer 56

insulator

Question 57

What happens to static charge when an insulator is charged?

Answer 57

The static charge remains localized and does not dissipate easily.

Question 58

Which of the following is a property of conductors? A) High resistance B) Low resistance C) No resistance

Answer 58

B) Low resistance

Question 59

True or False: Insulators can hold static charge for a long time.

Answer 59

True

Question 60

Name one common application of insulators.

Answer 60

Electrical insulation in wiring.

Question 61

What is static discharge?

Answer 61

The sudden flow of electricity between two electrically charged objects.

Question 62

Fill in the blank: The process of charging an object by rubbing it against another object is called __________.

Answer 62

triboelectric charging

Question 63

Which material is considered a good insulator? A) Copper B) Glass C) Silver

Answer 63

B) Glass

Question 64

True or False: Static electricity can be created by friction.

Answer 64

True

Question 65

What is the main cause of static electricity?

Answer 65

The imbalance of electric charges on the surface of objects.

Question 66

Name a common conductor used in electrical wiring.

Answer 66

Copper

Question 67

What happens during static discharge?

Answer 67

An electric charge is released, often resulting in a spark.

Question 68

Fill in the blank: Insulators are used to prevent the __________ of electricity.

Answer 68

unintended flow

Question 69

What is the role of insulators in electrical circuits?

Answer 69

To prevent electrical leakage and protect users from shock.

Question 70

True or False: Plastic is a good conductor of electricity.

Answer 70

False

Question 71

What is the term for materials that can act as both insulators and conductors under certain conditions?

Answer 71

Semiconductors

Question 72

Which of the following is NOT a property of conductors? A) Conduct electricity B) Have high resistance C) Allow heat transfer

Answer 72

B) Have high resistance

Question 73

True or false: insulators hold electrons tightly and are delocalized

Answer 73

false ## Footnote insulators hold electrons tightly and are localized

Question 74

do conductors have localized or delocalized electrons?

Answer 74

delocalized

Question 75

You want to measure the current running through a circuit element. What type of device would you use and how would you connect this device?

Answer 75

An ammeter; in series with the circuit element

Question 76

True or false: If two charges have the same sign, they repel each other, and as they move further apart (r decreases), their electric potential energy decreases. If two opposite-sign charges attract each other, as they get closer together (r increases), their electric potential energy decreases.

Answer 76

false ## Footnote r increases; r decreases

Question 77

What are the units of measurement for electric potential energy?

Answer 77

joules

Question 78

Conservation of charge means that electric charges:

Answer 78

can't be created or destroyed, but can be transferred.

Question 79

The term “voltage” refers to a change in which quantity?

Answer 79

electric potential

Question 80

Two charges separated by distance r store electric potential energy U. If the distance between the charges is reduced to r/3, what is the new value of the electric potential energy?

Answer 80

U' = 3 * [k * (q1 * q2) / r] U' = 3U

Question 81

True or false: Static discharge occurs when the net charge on an object moves to ground, leaving the object electrically negative

Answer 81

false ## Footnote Static discharge occurs when the net charge on an object moves to ground, leaving the object electrically neutral.