Physics paper 1 - Key Terms

What is the key term for the following definition: the number of unstable atoms that decay per second in a radioactive source?

• activity

• half-life

• isotope

• ionization

What is the key term for the following definition: When an unstable nuclei emits an alpha particle (made up of two protons and two neutrons)?

• alpha decay

• beta decay

• gamma emission

• electron capture

What is the key term for the following definition: electric current in a circuit that repeatedly reverses its direction?

• alternating current (AC)

• direct current (DC)

• static electricity

• resistance

What is the key term for the following definition: equal to the number of protons in a nucleus?

• atomic number

• mass number

• isotope

• atomic mass

What is the key term for the following definition: When a neutron turns into a proton (in the nucleus of an unstable atom) a high speed electron is also produced and emitted from the atom?

• beta decay

• alpha decay

• gamma emission

• electron capture

What is the key term for the following definition: an object or a group of objects for which the total energy is constant?

• closed system

• open system

• isolated variable

• dynamic equilibrium

What is the key term for the following definition: energy cannot be created or destroyed only transferred between stores?

• conservation of energy

• potential difference

• thermal expansion

• kinetic theory

What is the key term for the following definition: the number of radioactive counts per second detected by a Geiger counter?

• count rate

• half-life

• background radiation

• ionization energy

What is the key term for the following definition: mass per unit volume of a substance (Density = mass ÷ volume)?

• density

• volume

• weight

• pressure

What is the key term for the following definition: a component that only lets current pass through in one specific direction?

• diode

• resistor

• capacitor

• transistor