IB PHYSICS Topic 10: Fields

Gravitational Field

A region where a small test mass experiences a force due to another mass.

Electrostatic Field

A space where a small positive test charge experiences a force per unit charge.

Electric Potential

Given by electric potential difference (voltage) and represents the capacity for doing work by a change in position of the positive test charge.

Gravitational Potential

The work done per unit mass required to move a test mass from infinity to a point P in a gravitational field. It is always negative, with the potential at infinity being zero.

Field Lines

Show the path a test particle would take in a force field, revealing its direction and strength.

Equipotential Surfaces

Points with the same gravitational potential, forming surfaces. Field lines are normal to equipotential surfaces, and the density of field lines is proportional to field strength.

Electric Potential Energy

The capacity for doing work by a change in position of a positive test charge, given by Coulomb's constant, fixed charge, test charge, and radius.

Gravitational Potential Energy

The work done required to move an object from infinity to a point P in a gravitational field. It is always negative.

Potential Gradient

The change in gravitational potential per unit distance, related to gravitational field strength. It represents the slope of a graph plotting gravitational potential against distance from the mass.

Potential Difference

The work done by moving a positive test charge between two points in an electric field. It is required for current flow and is provided by cells or batteries.

Escape Speed

The minimum speed needed for an object to reach infinity from a planet's surface. Objects launched at or above escape speed won't return due to gravity.

Orbital Motion

Motion of an object in a circular path around another object, with gravitation providing the centripetal force.

Orbital Speed

The speed of an object in orbit, given by (GM/r)^0.5, where G is the gravitational constant, M is the mass, and r is the radius.

Orbital Energy

The sum of kinetic energy and gravitational potential energy for an orbiting satellite.

Inverse-Square Law

The behavior where the strength of a field decreases with the square of the distance from the source.

Inverse-Square Law Graphical Representation

Graphical representation of the inverse-square law behavior for gravitational and electric fields.

Gravitational Field

Graphical representation of the gravitational field in accordance with the inverse-square law.

Electric Field

Graphical representation of the electric field in accordance with the inverse-square law.