Radioactvity

Question 1

What is radioactivity

Answer 1

The spontaneous emission of a radioactive substance due to nuclear instability.

• Alpha
  -Positrons
  -Beta
  -Gamma

Question 2

Define Half Life

Answer 2

Average time taken for 1/2 radioactive particles to decay.

Question 3

Define Background Radiation

Answer 3

The radiation detected when no immediate source is present and is due to cosmic radiation

Question 4

Why is Radioactive decay said to be spontaneous

Answer 4

Random : cannot predict WHICH particle will decays at a specific time

Random: cannot predict HOW MANY particles will decay at a given time

Spontaneous: independent to external conditions

Question 5

Define Activity of a sample

Answer 5

The rate of decay of radioactive particles.
It is the product of the decay constant and the number of decayed particles.

Question 6

The Becaquerel (Bq)

Answer 6

The number of disintegrations per second
Unit of Activity

Question 7

Define Decay constant of a radioactive isotope

Answer 7

The probability that a radioactive nucleus of the isotope will decay in one second

It is the constant of proportionality relating activity to the number of undecayed particles

Question 8

Define a Tracer

Answer 8

Radioisotope that is added to a non-radioactive material in order to trace or monitor its position or measure its concentration

Question 9

What is Alpha decay ?

Answer 9

When An atom is by Alpha emissions it’s nuclear number decreases by 4 and its proton number by 2

Question 10

What is Beta Decay?

Answer 10

In beta decay a neutron changes to a proton and an electron. The proton remains in the nucleus, and the electron is emitted as a beta particle.

Question 11

What is Gamma emission ?

Answer 11

Energy emitted as a EM wave as the nuclear goes from an excited state to ground state

Question 12

Factors that affect activity

Answer 12

Number of particles
Number of undecayed particles
Half life
Decay constant