Atomic structure - Physics

Question 1

What does it mean if a substance is radioactive?

Answer 1

A substance is radioactive if it is unstable and gives out radiation at random intervals.

Question 2

Out of alpha, gamma and beta radiation which one has the highest penetrating power?

Answer 2

Gamma

Question 3

Which type of radioactive particle is the most ionising?

Answer 3

Alpha

Question 4

What properties does the plum pudding model have?

Answer 4

Solid ball of positive charge, which contains negative electrons

Question 5

Why is it important that the chamber is evacuated while performing the alpha particle experiment?

Answer 5

As there was no other significant particles in the air the alpha particles could reach the gold leaf.

Question 6

Most of the alpha particles went straight through the thin gold leaf. What does this mean?

Answer 6

The atom is mostly empty space.

Question 7

What are alpha particles ?

Answer 7

Helium nuclei

Question 8

How much of background radiation is naturally occurring?

Answer 8

85%

Question 9

What unit do we measure radioactive activity in?

Answer 9

Becqurel

Question 10

What is a half life?

Answer 10

The half life is the time it takes for the number of radioactive nuclei in an isotope to half.

Question 11

What is the half life equation?

Answer 11

Count rate = initial count rate/ 2 to the power of n

Question 12

What is irradiation?

Answer 12

Irradiation is when a surface is exposed to radiation

Question 13

What is contamination?

Answer 13

When an object is mixed with a radioactive substance