A uniform magnetic field is created when field lines between two opposite poles of bar magnets are parallel and evenly spaced.

The catapult field effect describes how electrical energy is converted into kinetic energy. It underpins the operation of electric motors and loudspeakers by allowing charged particles to be accelerated by an electromagnetic field.

Magnetic effects arise because sets of charges that produce the fields are moving relative to each other in different frames of reference.

Fields can be depicted using visual models, quantified by field strength and potential, and analyzed through vector field theory for complex understanding.

Use the right-hand corkscrew rule to determine the direction of the magnetic field created by a current. Point your thumb in the direction of the current, and your fingers will curl in the direction of the field lines. Fleming's left-hand rule is used to find the force direction on a current-carrying conductor in a magnetic field: point your thumb in the direction of motion (force), forefinger in the direction of the field, and middle finger in the direction of the current.

F = qvB sin(θ), where F is the force, q is the charge, v is velocity, B is magnetic field strength, and θ is the angle between v and B.

Angle θ is defined as the angle between the velocity vector of the moving charge and the magnetic field lines.

Downwards. According to Fleming's left-hand rule, if the magnetic field is right, and current flows into the page (thumb points in), the force (first finger) is downwards.

Circular field lines surround the wire, with the direction determined by the right-hand rule. Their center aligns with the wire and their density decreases with distance from it.

μ0 = 4π × 10–7 N A–2 (tesla meter per ampere).

Visualizing field lines as elastic can aid understanding. When objects move, shorter field lines imply the field has done work, leading to a lower energy state for the objects.

Field lines illustrate the direction and strength of forces in electromagnetic fields. By observing field lines, one can infer the direction of force on a charged particle, with closer lines indicating stronger forces. This helps understand the behavior of particles in electromagnetic fields due to attractive or repulsive interactions.

The wire's circular magnetic field combines with the magnets' uniform field, resulting in a complex pattern. The resultant field is typically weaker below the wire than above due to this interaction.

By using direction rules, like Fleming’s left-hand rule. Your index finger points in the direction of the magnetic field, the second finger in the direction of the current, and the thumb shows the direction of the force on the wire.

Magnetic force on a straight wire is proportional to the wire's length (L) and the current (I) flowing through it.

B = F / (I × L)

The Earth's magnetic field is roughly 10⁻⁴ T.

F = BIL sin θ

The force quadruples. Magnetic force (F) is given by F = qvBsin(θ), so if charge (q) and velocity (v) are both doubled, the force becomes 4 times greater (4F).

To find the magnetic field strength (B), use the formula F = BIL, where F is the force (14mN), I is the current (3.5A), and L is the length of wire (4.0cm = 0.4m). Rearranging for B gives B = F / (I*L). Substituting the values, B = 14mN / (3.5A * 0.4m) = 0.1T, so the magnetic field strength is 0.1 Tesla.

The study of motion, focusing on *how* things move, not *why*.

Change in position; a **vector** (magnitude and direction).

Rate of change of displacement; a **vector**. Speed with direction.

Rate of change of velocity; a **vector**. How quickly velocity changes.

Rate at which an object travels over a distance. It is a **scalar** quantity (magnitude only).

Magnitude only (e.g., speed, mass, distance).

Magnitude and direction (e.g., velocity, force, displacement).