All Flashcards
How does the force on an alpha particle moving through a magnetic field at an angle relate to its acceleration?
Acceleration (a) equals force (F) divided by the particle's mass (m). The force and resulting acceleration are perpendicular to the particle's velocity, which means while the particle's direction changes, its speed remains constant.
How do you calculate the magnetic field strength (B) created by a long straight wire carrying current I at a point situated at distance r from the wire?
B = μ0I / (2πr), where B is the magnetic field strength, μ0 is the magnetic constant (4π x 10^-7 Tm/A), I is the current, and r is the distance from the wire.
How does the magnetic field strength vary with distance from a long straight conducting wire?
The magnetic field strength around a long straight wire decreases inversely with distance from the wire, following a 1/r relationship, where r is the distance from the wire.
What force acts on wire 2 due to the interaction with the magnetic field from wire 1?
F = B × I2 × L
What is the formula for the force per unit length on a second wire caused by the first wire?
F/L is calculated using the formula μ0 I1 I2 / (2πr), where F is the force, L is the length of the wire, μ0 is the permeability of free space, I1 and I2 are the currents in wires 1 and 2, and r is the distance between the wires.
Why does Ampère's law follow a 1/r relationship rather than an inverse-square law?
Ampère's law applies to a long wire, which constrains the electromagnetic field to two dimensions. As a result, the field lines spread out in a plane rather than in space, leading to a linear decrease with distance, hence the 1/r relationship.
How was the ampere defined pre-2019?
Before 2019, an ampere was defined by the force between two infinite parallel conductors, a meter apart in a vacuum, which was 2π × 10–7N per meter.
What is the direction of force on an electron in a downward uniform electric field between two parallel plates?
The force acting on the electron is upwards.
How is the vertical acceleration of an electron in an electric field related to the electric force and the electron's mass?
The vertical acceleration (a_vertical) of an electron in an electric field is given by F/m_e, where F is the force on the electron, m_e is its mass, q is its charge, E is the electric field strength, V is the potential difference, and d is the separation distance. Thus, a_vertical = qE/m_e = (q/m_e)(V/d).
How do you calculate the vertical velocity of an electron when it exits the plates with an initial vertical speed of zero?
To calculate the vertical component of velocity as the electron exits the plates, multiply the vertical acceleration (a) by the time (t) the electron is subjected to the acceleration: v = at.
What is position?
Where an object is located, measured in meters (m).
What is velocity?
How fast an object is moving and in what direction, measured in meters per second (m/s).
What is acceleration?
How much an object's velocity is changing over time, measured in meters per second squared (m/s²).
What is free fall?
When an object falls under the influence of gravity alone.
Define a scalar quantity.
A quantity with magnitude only.
Define a vector quantity.
A quantity with both magnitude and direction.
Who was Ampère's law named after and what did he call his discoveries?
Named after André-Marie Ampère. He called his discoveries electrodynamics.
Who was able to confirm Ampère’s law through experiments and created the first electric motor?
British physicist Michael Faraday.
What are the ways to multiply vectors and what do they result in?
Vectors can be multiplied using the scalar (dot) product, resulting in a scalar quantity that represents the magnitude of one vector's component along another's direction. The vector (cross) product results in a vector that is perpendicular to the plane formed by the original vectors and has a magnitude representing the area of the parallelogram spanned by the vectors.
What is the difference between scalar and vector multiplication regarding their results?
Scalar multiplication yields a scalar, and its result only has magnitude. On the other hand, vector multiplication gives a vector, which has both magnitude and direction.
What is the relationship between the vertical electric field, potential difference, and distance between plates?
E = V/d, where E is the electric field strength, V is the potential difference, and d is the distance between the plates.
What is the trajectory shape of the electron due to the uniform electric field?
The trajectory of the electron is a parabola.
Why can we neglect gravitational effects on electron motion in an electric field?
Electrons are much more affected by electric forces than gravity, making gravitational acceleration (9.8 m/s²) negligible in comparison.
What path does an electron take in a uniform magnetic field?
In a uniform magnetic field, an electron moves in a circular path with the magnetic force providing the centripetal force that keeps it in motion around the field lines.
When an electron enters a magnetic field at an angle that isn’t 90° to its direction, what happens to its motion?
It moves in a helical path. The perpendicular component leads to a circular motion and the parallel component continues in its original direction.
What is the orientation of magnetic force exerted on a moving charged particle in a magnetic field?
The magnetic force acts perpendicular to both the velocity of the charged particle and the magnetic field lines.