Nuclear physics and Astronomy & cosmology

Question 1

Formula

Einstein’s mass-energy equation

Answer 1

Energy = change in mass * (speed of light)^2

Question 2

Definition

Mass defect

Answer 2

Difference between total mass of individual nucleons and mass of nucleus

Question 3

Definition

Binding energy

Answer 3

Min external energy required to completely seperate all the nucleons to infinity

Question 4

Definition

Fission

Answer 4

Massive nucleus splits into 2 smaller nuclei

Question 5

Definition

Fusion

Answer 5

2 light nuclei join together to form a heavier nucleus

Question 6

Definition

Decay constant

Answer 6

Propability that an individual nucleus will decay per unit time

Question 7

Definition

Activity

Answer 7

Rate of decay of a nuclei of a radioactive source

Question 8

Formula

Activity equals

Answer 8

-decay constant * number of undecayed nuclei

Question 9

Definition

Count rate

Answer 9

The number of particles or photons detected by a Geiger-Muller tube. Always a fraction of the activity

Question 10

Definition

Half-life

Answer 10

Mean time taken for half of the active nuclei in a sample to decay

Question 11

Formula

Equations for radioactive decay

Answer 11

X = max X * exp^(-time * decay constant)