Chapter 6 Principles of Radiologic Physics and Dosimetry

Question 1

Dimension of atom

Answer 1

10(power -10) m

Question 2

Dimension of nucleus

Answer 2

10(power -14) m

Question 3

Rest mass of an electron(me)

negative electric charge of an electron

Answer 3

9. 109 x 10(-31) kg

1. 602 x 10(-19) coulomb

Question 4

Density of nucleus

Answer 4

10(power 15) kg/m3

Question 5

Nucleons composed of?

Answer 5

Protons + Neutrons

Question 6

Rest mass of Proton (mp)

Positive electric charge of Proton

Answer 6

1. 673 x 10(-27) kg

1. 602 x 10(-19) Coulomb

Question 7

Rest mass of Neutron(mn)

Electric charge of Neutron

Answer 7

1.675 x 10(-27) kg

No electrical charge

Question 8

Units of atom for
Mass
Distance
Energy
Electrical charge

Answer 8

amu (Atomic Mass Unit)
nm (NanoMeter) 1nm = 10(-9) m
eV (electron Volt)
e (electronic charge) 1 e = 1.602 x 10(-19) C

Question 9

Define Atomic Mass Unit

Answer 9

1/12 the mass of the neutral carbon-12 atom

Question 10

Conversion of amu to kg

Answer 10

1 amu = 1.660 x 10(-27) kg

Question 11

Define electron volt(eV)

Answer 11

Kinetic energy required by an electron accelerated through potential difference(voltage) of 1 volt(V)

1 eV = 1.6 x 10(-19) joule(J) of energy

Question 12

Maximum number of electrons allowed in each shell is given by

Answer 12

2n(power 2)

Question 13

Atomic number(Z) equals to
Atomic mass number(A) equals to

Answer 13

Z equals to number of protons(P) in the nucleus

A equals to number of nucleons(P+N)

Question 14

What is the atomic number(Z) and atomic mass number(A) of cobalt

Answer 14

Z = 27(P)
A = 60(27P + 33N)

Question 15

Define Isobar and Isotone and Isotope

Answer 15

Isobar has same mass number but different proton and neutron numbers eg 60/27 Co and 60/28 Ni

Isotones has same number of neutrons but different atomic and mass numbers eg 57/27 Co and 56/26 Fe

Isotopes have same atomic number but different number of neutron and therefore different mass number eg 58/27 Co 59/27 Co 60/27 Co