nuclear 2 Flashcards Preview

Physics year 1 > nuclear 2 > Flashcards

Flashcards in nuclear 2 Deck (14)
Loading flashcards...

Why can't alpha particles travel far in air?

Because it quickly loses its kinetic energy to passing particles; due to its high rate of ionisation


'How much' does an alpha particle ionise?

Around 10,000 air particles per 1mm


'How much' does a beta particle ionise?

Around 100 air particles per 1mm


'How much' does gamma ionise?

Around 1 air particle per 1mm


Why can gamma travel very far in air?

It has a low rate of ionisation, therefore not losing all its kinetic energy by ionising passing particles, resulting in being able to travel very far.


Why can alpha particles be deflected in electric and magnetic fields?

Because they are positively charged, therefore and therefore repel in a positive field would repel and attract in a negative.
Its deflection is not too great due to its large mass.


Why can beta particles be deflected by magnetic and electric fields?

Because they are negatively charges, therefore a positive field would attract and negative field repel.
Can be deflected a lot due to small mass.


Why cannot gamma particles be deflected by magnetic and electric fields?

They are neutrally charged and have no mass, therefore not affected by charged fields.


What is a radiation dose?

Energy absorbed per kg of a body


What is a doses equation, measurement and unit?

D=E/m (energy/mass)
Measured in J per kg, called Grays (Gy)


What happens if ionisation takes place in the body?

-mutation of DNA, leads to cancer
-ions produced in the body damages the cells
-alters functions of enzymes


Why are alpha particles more ionising than gamma?

Because Alpha particles carry more energy, and the more energy the greater the range and amount of particles can be ionised.


Why can ionisation occur in the body due to radition?

The body's molecules require a few eV to ionise, although Alpha, Beta and Gamma each carry several MeV of energy.
REPHRASE: Resulting in it being very easy to ionise many particles


Name three radio active safety precautions taken in school.

-sources must be kept in lead-lined containers, stored in a metal cupboard
-sources are kept away from the body and handled with tongs
-when used, sources are only used for a short period of time.