The evidence for the nucleus (10)

Question 1

Rutherford scattering

Answer 1

gives evidence for the nuclear model of the atom.

Question 2

Isotope

Answer 2

different isotopes of an element have the same number of protons but different numbers of neutrons.

Question 3

Alpha particles

Answer 3

helium nuclei.

Question 4

Beta particles

Answer 4

fast-moving electrons.

Question 5

Gamma rays

Answer 5

high-energy photons of electromagnetic radiation, which carry energy away from an unstable nucleus.

Question 6

Femtometre

Answer 6

nuclear radii and diameters are measured in femtometres, 10-15m. The unit is abbreviated to fm.

Question 7

Empirical

Answer 7

the equation r=r_0 A^(1/3) is an empirical equation. The word ‘empirical’ means that the equation is based purely on experimental results. It is not exact, but it gives an approximate value for a nuclear radius.

Question 8

Atomic mass unit

Answer 8

one atomic mass unit (1u) is equal to 1.67×〖10〗^(-27)kg.

Question 9

Becquerel

Answer 9

the activity of a radioactive source is equal to the number of particles emitted per second. The unit of activity is the becquerel (Bq): 1 becquerel (1Bq) = an emission of one particle per second.

Question 10

Ionising radiation

Answer 10

is dangerous because ions are produced in our bodies, which damage cells and the functions of enzymes are changed.

Question 11

Dose

Answer 11

the energy absorbed per kilogram of a body.

Question 12

Gray

Answer 12

the unit of dose is Jkg-1, which is called one gray (Gy).

Question 13

Dose equivalent

Answer 13

the measure of the damage done by radiation.

Question 14

Sievert

Answer 14

the unit of dose equivalent is also Jkg-1, but for dose equivalent the unit is called the sievert (Sv).