Physics key terms

The state of an object that has gained electrons and therefore has more electrons than protons.

A thermistor for which resistance decreases as temperature increases.

The overall change after all increases and decreases have been combined.

The overall charge of a body after its positive and negative charges have been combined.

The reduction in an emission compared with its initial value, often expressed as a fraction or ratio of the initial emission.

The overall force after all the forces acting have been combined, taking their directions into account.

The resistance of a single resistor that would have the same overall effect as a group of resistors.

Having no overall electric charge because the total positive and negative charges balance.

A condition in which upthrust equals weight, so an immersed object has no resultant vertical force.

An object with equal total positive and negative charge, so it has no overall charge.

The blue conductor that completes the normal circuit and is at or close to earth potential, approximately 0 V.

An electrically neutral particle found in an atomic nucleus, with approximately the same mass as a proton.

Radiation consisting of neutrons emitted from unstable nuclei.

An extremely dense remnant that can be left after a supernova.

The SI unit of force, with symbol N.

An instrument containing a spring and a calibrated scale that measures force in newtons.

A calibrated spring balance used to measure force in newtons.

The law relating an object's resultant force, mass and acceleration: $F=ma$.

The law stating that when two objects interact, each exerts a force on the other that is equal in magnitude and opposite in direction.

A point on a stationary wave that does not vibrate.

A push or pull acting between objects that are not touching.

An interaction that can occur when the objects are separated, through a field.

A circuit element whose current–potential difference graph is curved, showing that its resistance changes between operating points.

A relationship in which force is not proportional to extension, producing a curved force–extension graph.

A relationship represented by a curve rather than a straight line; the rate at which one variable changes relative to the other is not constant.

An energy resource that is not replenished as quickly as it is used and will eventually run out.

A finite energy resource that is not replenished as quickly as it is used and will eventually run out.