Nuclear Physics

Question 1

neutral atom

Answer 1

consists of an equal number of protons and electrons

Question 2

electrons + their charge

Answer 2

very light negatively charged particles orbiting the nucleus
charge is -1e

Question 3

protons + their charge

Answer 3

massive positively charged particles located in the nucleus
charge is +1e

Question 4

neutrons

Answer 4

massive uncharged particle located int he nucleus of the atom

Question 5

nucleons

Answer 5

protons and neutrons located in the nucleus of the atom

Question 6

alpha particle [4,2] α or [4,2] He
+ charge

Answer 6

a helium nucleus consisting of 2 protons and 2 neutrons
has a charge of +2e (4 nucleons)

Question 7

nucleon number (A)

Answer 7

number of protons and neutrons in the nucleus of the atom

Question 8

ionisation

Answer 8

process by which a neutral atom loses or gains electrons

Question 9

background radiation

Answer 9

naturally occurring radiations in the environment due to building, food, cosmic rays, rocks

Question 10

ionising radiations + their symbols

Answer 10

• alpha particles , α
  -beta particles , β
• gamma radiations , γ

Question 11

properties of alpha, beta and gamma radiation
[nature, charge, mass, ionising ability, speed, penetration ability

Answer 11

NATURE
α - helium nucleus
β - fast moving electron
γ - photon of E.M. radiation
CHARGE
α - +2e
β - -1e
γ - 0
MASS
α - most massive
β - more massive than gamma
γ - least massive
IONISING ABILITY
α - most ionising (massive & slow)
β - more ionising than gamma
γ - least ionising
SPEED
α - slowest at 1.5x10^8 m/s
β - faster than α at 2.7x10^8 m/s
γ - fastest at 3.0x10^8 m/s (cause part of e.m. spectrum)
PENETRATION ABILITY
α - absorbed/stopped by sheet of paper
β - stopped by thin aluminium sheet OR many sheets of paper
γ - weakened by lead of 1m concrete wall

Question 12

deviation of alpha, beta and gamma radiation in electric field and magnetic field

Answer 12

ELECTRIC FIELD
α - lightly deviated
β - heavily deviated
γ - not deflected
MAGNETIC FIELD
α - lightly deviated as per Flemings left hand rule
β - heavily deviated as per Flemings left hand rule
γ - not deflected as it has no charge

Question 13

radioactive decay

Answer 13

the random unspontaneous emission of ionising radiation from nucleus of instable nuclide

Question 14

meaning of random

Answer 14

every nucleus has an equal chance of decaying

Question 15

meaning of sponateous

Answer 15

decay is not affected by any external factors such as temp., geographical location, weather, pressure etc.

Question 16

types of radioactive decay

Answer 16

beta - decay
a neutron in the nucleus breaks down into a proton and an electron. The electron is ejected pit and the proton is retained
proton n.o. increases by 1 , neutron n.o. decreases by 1 but nucleon n.o. remains unchanged

Question 17

nuclear fission

Answer 17

when a large unstable nuclide splits into 2 lighter and stable nuclide followed by emission on energy

Question 18

nuclear reactor

Answer 18

a device used to initiate and control a nuclear fission chain reaction

Question 19

where are nuclear reactors used?

Answer 19

at power plants for electricity generation and in nuclear propulsion

Question 20

how can heat from nuclear fission be used?

Answer 20

heat from nuclear fission is passed to a working fluid (water or gas), which in turn runs through steam turbines. these either drive up a ships propellors or turn electrical generators’ shafts

Question 21

energy from nuclear reactions is converted into…

Answer 21

1.kinetic energy of the product
2.heat

Question 22

nuclear fusion

Answer 22

when 2 light nuclei combine to form a relatively heavier and stable nuclide followed by emission of energyl

Question 23

in most stars, how is energy produced? + how does it occur and why?

Answer 23

by the nuclear fusion reaction of isotopes of hydrogen. it occurs under very high temperatures to provide sufficient kinetic energy for the fusing nuclei to overcome repulsion between their individual nucleus

Question 24

in stars, energy is given off under 3 types of waves. what are they called?

Answer 24

1. infrared radiations that transfer heat
2. light
3. visible light, so that we are able to see