29- Modern Physics

The release of electrons from the surface of a hot metal

Streams of high speed electrons moving from the cathode to the anode

**check book**

The energy gained or lost by an electron when it moves through a potential difference of 1 V.

1 eV = 1.6×10^-19 J

The release of electrons from the surface of a metal by electromagnetic radiation of a suitable frequency

For a given metal is the minimum frequency needed for photoemission to occur

Of a metal is the minimum energy needed to remove an electron from the surface of the metal

A packetundle of Electromagnetic radiation

High frequency electromagnetic radiation

Produced when light from a luminous source undergoes dispersion

of an element is the number of protons in the nucleus. (Z)

of an element is the total number of protons and neutrons in the nucleus. (A)

Atoms of the same element that have the same number of protons but different number of neutrons

The decay of unstable nuclei with the emission of one or more types of radiation

Fast moving helium nuclei ejected from the nuclei of radioactive atoms

High speed electrons ejected from the nuclei of radioactive atoms

High frequency electromagnetic radiation emitted from the nuclei of radioactive atoms

The breaking up of neutral atoms into positive and negative ions

The activity of a radioactive sample is the number of nuclei decaying per second

1 Becquerel is equal to 1 disintegration per second

States that the number of nuclei decaying per second (the activity)

is directly proportional to the number of nuclei undecayed

The half-life of a radioactive sample is the time taken for half the nuclei present to decay

OR

the time taken for its activity to decrease by half

**say the top one if asked to define**

The splitting up of a large nucleus into two smaller nuclei of roughly the same size with the release of energy.

The joining of two small nuclei to form a larger nucleus with the release of energy.