Physics paper 1 - Key Terms and Definitions

What is the definition of Activity in physics?

• the number of unstable atoms that decay per second in a radioactive source

• the time taken for half of a radioactive material to decay

• the speed at which an object moves in a straight line

• the force required to move an object a certain distance

What is Alpha radiation (α)?

• When an unstable nuclei emits two protons and two neutrons

• When an atom absorbs a neutron and splits into two smaller nuclei

• When an electron is emitted from the nucleus of an atom

• When energy is released in the form of electromagnetic waves

What is Alternating current (a.c.)?

• electric current in a circuit that repeatedly reverses its direction

• electric current that flows only in one direction

• a type of current that does not flow through conductors

• a current that is always constant in magnitude and direction

What is the definition of Atomic number?

• Number of neutron in an atom

• Number of protons in an atom

• Number of neutrons and protons combined

• Numbed of neutrons, protons and electrons combined

What is Beta radiation (β)?

• When a nucleus releases 2 protons and 2 neutrons

• When a proton turns into a neutron and an electron

• When a neutron turns into a proton and an electron

• When the nucleus changes shape to become more stable

What is a Closed system in physics?

• an object or a group of objects for which the total energy is constant

• an object that can exchange both energy and matter with its surroundings

• a system where only matter is exchanged with the surroundings

• a system that is isolated from all forms of energy and matter exchange

What is the law that says energy is never created or destroyed but only transferred from one form to another?

• Conservation of momentum

• Newtons second law

• Conservation of energy

• Law of efficiency

What is Count rate in the context of radioactivity?

• the number of radioactive counts per second detected by a Geiger counter

• the amount of energy released during radioactive decay

• the time taken for half the radioactive atoms to decay

• the mass of a radioactive sample

What is Density?

• mass per unit volume of a substance (Density = mass ÷ volume)

• volume per unit mass of a substance (Density = volume ÷ mass)

• mass per unit area of a substance (Density = mass ÷ area)

• weight per unit volume of a substance (Density = weight ÷ volume)

What is a Diode?

• a component that only lets current pass through in one specific direction

• a device that stores electrical energy

• a component that amplifies signals

• a device that generates alternating current