IB SL Physics > Fields > Flashcards

Fields Flashcards

(83 cards)

Study These Flashcards
1
Q

What did Kepler discover his laws of orbital motion through?

A

Empirical observation: Relying on observations or experimental data, rather than theories.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Kepler’s first law of orbital motion

A

Each planet orbits the sun along an elliptical path. The sun is located at a focus point of the elliptical orbit.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Kepler’s second law of orbital motion

A

The imaginary line joining the sun and a planet sweeps equal areas of space in equal time intervals as the planet followsnits orbit.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Orbital radius

A

The distance between the center of the source of the gravitational field and the object orbiting

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Keplers third law of orbital motion

A

The square of the orbital period of a planet is directly proportional to the cube of the average distance of the planet to the sun.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Orbital period

A

The time it takes an object to complete one full orbit

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Newton’s universal law of gravitation

A

Every object in the Universe attracts every other object with a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between their centres. The direction of the force is along the line joining the objects.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Gravitational field

A

An area of space where a mass experiences a gravitational force.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Where do gravitational fields exist?

A

Around all objects with mass

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Range of gravitational fields

A

Gravitational fields have infinite range. Every gravitational field extends for an infinite distance. However, the field becomes very weak at large distances away from the mass that is the source of the field.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Gravitational field lines

A

Lines that show the direction of the gravitational force acting on a mass at that point in a gravitational field.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

The closer together the gravitational field lines

A

The stronger the gravitational field

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Gravitational field strength

A

Gravitational force per unit mass experienced at a point in a gravitational field.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

When can gravitational field strength be zero?

A

Gravitational field strength is a vector, so the direction is important. Therefore, if 2 magnitudes are equal and in opposite directions, then there is no resultant gravitational field at that point.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the fundamental property of matter that describes its ability to experience electric force?

A

Electric charge

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What does it mean that electric charge is “quantized”?

A

It means charge can only exist in discrete values, which are integer multiples of a base value.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Why is the electric force considered a “field force”?

A

It acts at a distance.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is the law of conservation of charge?

A

Electric charge cannot be created or destroyed, only moved from one place to another; the total charge of an isolated system is conserved.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

In electric circuits, what type of charge flows?

A

Negative charge (electrons)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Grounding

A

Connecting an object to earth so that any excess charge can flow to the earth and neutralise the object in question.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What happens when a negatively charged object touches the Earth?

A

Negative charges (electrons) transfer from the object to the Earth, making the object neutral. Because the Earth is vast, it does not become noticeably charged.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What happens when a positively charged object touches the Earth?

A

Negative charges (electrons) transfer from the neutral Earth to the object, making the object neutral.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Electrostatic induction

A

Charging a neutral object by bringing another, already charged object close to it, then removing the earth connection from the second object.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Transferring charge through friction characteristics (3)

A
  • There is contact and relative motion between the objects.
  • Negative charge transfers from one object to the other.
  • The two objects become charged with opposite charges.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Transferring charge through electrostatic induction characteristics (4)
- There is no contact between the objects. - The charge of one object is redistributed. - If this object is connected to a grounding wire, negative charges are transferred to the Earth. - The two objects become charged with opposite charges.
26
Transferring charge through contact characteristics (3)
- There is contact between the objects. - Negative charge transfers to the more positively charged object. - The two objects become charged with the same amount of charge.
27
Coulomb's law
The size of the force between two charged particles is proportional to the product of their charges and inversely proportional to the square of the distance between them.
28
Permittivity
The ease with which an electric field can pass through a substance. The higher the permittivity of the substance, the higher the resistance to the electric
29
What is the Coulomb constant dependent on?
(E.0) which is the permittivity of free space.
30
Electric field
A region of space where an electric charge experiences a force.
31
How to test the strength of an electric field?
In order to test how strong the electric field is we bring a small positive charge q inside the field. This is called the test charge. The test charge feels an electric force F because of the electric field around the source charge.
32
Electric field strength
The force per unit charge experienced by an electric charge.
33
Electric field lines
Used for visualising electric fields. The arrow on each field line shows direction as they point towards the negative charge, and the density of the field lines indicates the field strength.
34
What do electric field lines represent regarding force?
They show the direction of the electric force acting on a positive test charge placed in the field.
35
Describe the electric field lines for a positive point charge.
They are directed radially outwards (repulsive).
36
Describe the electric field lines for a negative point charge.
They are directed radially inwards (attractive).
37
How does a positive charge move when placed on a field line?
It will move along the line in the direction of the arrow.
38
What does the density (closeness) of field lines indicate?
Closer lines (higher density) indicate a stronger electric field, while farther apart lines indicate a weaker field.
39
Why are field lines closer together near a point charge?
To show that the electric field is stronger closer to the source.
40
Do electric field lines ever cross?
No, because the field at any point has a unique direction. If they crossed, the field would have two different directions at that spot.
41
Is the electric field of a point charge constant in direction?
No, it is a radial field, meaning the direction changes based on where you are around the charge.
42
What is the general direction of electric field lines between two oppositely charged plates?
The electric field lines are directed from the positively charged plate to the negatively charged plate.
43
In what direction do electric field lines travel if both parallel plates are positive or both are negative?
The field lines travel from the most positive (higher charge density) plate to the least positive (lower charge density)
44
How is the density of electric field lines related to the strength of the electric field?
The density (spacing) of the lines represents the strength. Equally dense/spaced lines indicate a constant field strength, while changing density indicates changing strength.
45
Unifrom field
A uniform field is an electric field that has the same direction and constant strength at all points within a given area, typically found between parallel plates.
46
What does it mean if the electric field lines between two plates have the same density at all points?
It means the electric field is uniform (constant strength) throughout that region.
47
What was the purpose of the 1909 Millikan oil drop experiment?
To measure the electric charge of a single electron and provide evidence that electric charge is quantized.
48
Example of permanent magnet
bar magnets
49
Example of a temporary magnet
electromagnet
50
Magnetic field lines
An aid for visualising magnetic fields. The arrow on each field line shows direction as they point towards the south pole and away from the north pole. The density of the field lines indicates the field strength.
51
How do magnetic field lines behave outside and inside a magnet?
They originate from the North pole and are directed towards the South pole outside, forming closed loops that continue inside.
52
What do the density and direction of magnetic field lines represent?
The density represents the strength of the magnetic field, and they show the direction of the magnetic force.
53
Can magnetic field lines intersect?
No
54
What is the shape of the magnetic field around a straight current-carrying wire?
The field lines are circular, with higher density (stronger) close to the wire and lower density (weaker) further away.
55
What happens to the magnetic field if you reverse the current direction in a wire?
Reversing the current reverses the direction of the magnetic field.
56
What is a solenoid?
A solenoid is a coil of wire with many loops
57
How is the magnetic field inside a solenoid described?
The magnetic field inside a solenoid is uniform.
58
Which type of magnet has a magnetic field similar to a solenoid?
A bar magnet
59
Magnetic field
A region of space where a magnetic material experiences a force.
60
The right-hand rule
Used to link together the force on a (positive) charge, the direction of the magnetic field present, and the force (due to movement in that magnetic field) acting on the charge during electromagnetic induction.
61
What is the right-hand rule used for?
To determine the direction of a magnetic field
62
Right-hand rule for a straight wire
Thumb: direction of current Curled fingers: direction of the magnetic field around the wire.
63
Right-hand rule for a circular coil
Thumb: direction of current, around the loop Curled fingers: direction of the magnetic field inside the coil
64
Right-hand rule for a solenoid
Thumb: direction of current, flowing around the solenoid windings Curled fingers: direction of the magnetic field inside the solenoid (points towards the North pole)
65
What determines the acceleration of a charged particle in a non-uniform electric field?
The acceleration varies depending on the specific point in space where the particle is located.
66
What determines the acceleration of a charged particle in a uniform electric field?
The particle experiences a constant acceleration.
67
How does acceleration in an electric field differ from acceleration in a gravitational field?
Gravitational acceleration depends only on mass, whereas electric field acceleration depends on both the charge and the mass of the particle.
68
If two particles have identical charges but different masses, how does their acceleration compare in the same electric field?
They will experience different magnitudes of acceleration.
69
If two particles have identical masses but different charges, how does their acceleration compare in the same electric field?
They will experience different magnitudes of acceleration.
70
What is the nature of the acceleration of a charged particle in a uniform electric field?
The particle experiences constant acceleration, similar to projectile motion or free fall in a uniform gravitational field.
71
In which direction does a positively charged particle accelerate in an electric field>
It accelerates in the same direction as the electric field vector
72
In which direction does a negatively charged particle accelerate in an electric field?
It accelerates in the opposite direction to the electric field vector.
73
The right-hand slap rule for a moving charged particle in a magnetic field
Can be used to predict the direction of the magnetic force acting on a positively charged particle. Hold your hand flat, with your thumb at right angles to your fingers. Thumb: Direction of motion of a positive charge. Fingers: Direction of magnetic field Palm: Force acting on the conductor Point your Fingers in the direction of the Field (another way to remember this is: there are many fingers and many field lines), and your thumbs in the direction of conventional current, then the direction of a slap with your palm is the direction of the outcome: the force.
74
Conventional current
The flow of positive charge, so if the particle is positively charged, the slap rule shows the direction of the force. If the particle is an electron or other negatively charged particle, the force acts opposite to the direction shown by the right-hand slap rule.
75
What is the direction of the magnetic force acting on a charged particle relative to its velocity?
The magnetic force is always perpendicular to the velocity of the particle (acting as a centripetal force).
76
Why does a magnetic field do no work on a moving charged particle?
Because the magnetic force is always perpendicular to the velocity, there is no component of the force acting in the direction of motion.
77
How does the kinetic energy of a charged particle change while traveling through a uniform magnetic field?
The kinetic energy remains constant (no energy changes), as the magnetic field only changes the direction of motion, not the speed.
78
What happens to the momentum of a charged particle in a magnetic field?
The momentum changes. Even though speed is constant, momentum is a vector and the direction of the velocity is constantly changing.
79
What path does a particle follow when moving perpendicular to a uniform magnetic field?
A circular path, because the magnetic force acts as a centripetal force of constant magnitude.
80
In the absence of other external forces, is a particle's speed in a magnetic field constant?
Yes, because the magnetic force does no work on the particle.
81
What condition must be met for a moving charged particle to experience a force in a magnetic field?
The particle's velocity must have a non-zero component perpendicular to the magnetic field
82
How is the total magnetic force on a current-carrying conductor in an external field defined?
It is the resultant (vector sum) of all the individual magnetic forces experienced by the moving electrons inside the conductor.
83
What two concepts are connected to explain why a wire moves when placed in a magnetic field?
1. Moving charges (current) create their own magnetic field. 2. External magnetic fields exert a force on moving charges.
IB SL Physics
flashcards
Decks in class (5)
# Cards
Brainscape helps you reach your goals faster, through stronger study habits.
© 2026 Bold Learning Solutions. Terms and Conditions