EP025 Note #KMKK

QUESTION

9.1 de Broglie wavelength

1. If the following particles have the same de Broglie wavelengths when they are accelerated in
electric field, which one has the highest velocity?

A. electron
B. proton
C. deuterium
D. helium ion

2. Which of the following cases shows that electron have wave-like characteristics

A. Diffraction of electron by crystal.
B. Emission of electron from hot cathode
C. Excitation of atom to produce line spectrum
D. Change of kinetic energy of electron to X-rays in X-ray tube.

3. The de Broglie wavelength,  of a particle of mass, m moving at a velocity v is given as

A.   mv

B.   mv
h

C.   hmv

D.   h
mv

4. A neutron has a mass of 1.6710–27 kg. The de Broglie wavelength is 1.4  10–10 m. How
fast is the neutron going? (in m s-1)

A. 3.4  103
B. 2.8  103
C. 3.9  103
D. 2.6  103

5. (a) Define wave particle duality

(b) De Broglie relation for wave –particle duality is given by   h Which quantity of
p

the relation represents the wave and the particle?

6. In a photoelectric effect experiment, a light source of wavelength 550 nm is incident on a
sodium surface. Determine the momentum and the energy of a photon used.
(Given the speed of light in the vacuum, c =3.00×108 m s-1 and
Planck’s constant, h =6.63×10-34 J s)

149

8. (a) An electron is accelerated from rest through a potential difference of 2000 V.
Determine its de Broglie wavelength.

(b) An electron and a photon has the same wavelength of 0.21 nm. Calculate the
momentum and energy (in eV) of the electron and the photon.
(Given c =3.00×108 m s-1, h =6.63×10-34J s, me=9.11×10-31 kg and e=1.60×10-19C)

9. (a) Give two examples where matter shows wave-particle like characteristic.
(b) Calculate the de Broglie wavelength for a proton moving with a speed of 1.00×106 m
s-1.

10. Calculate the de Broglie wavelength for an electron that has kinetic energy :
(a) 50.0 eV and
(b) 50.0 keV.

9.2 Electron Diffraction
11. An electron of mass m moves at a speed close to the speed of light through space in t second.

The elctron acts like
A. a particle with momentum
B. a particle with wavelength
C. a wave with length
D. Both a particle and wave
12. Electrons are used in an electron microscope to produce high resolution power. This is
because
A. electron moving at hihgh speed change to visible light
B. electrons moving at high speed have wave-like properties
C. electron moving at high speed heve high wavelength
D. electrons moving at high speed have gigh penetration power
13. (a) Describe the Davisson-Germer experiment by using the schematic diagram to show

electron diffraction.
14. Give two advantages of electron microscope compare to optical microscope

150

151

152

153

154

155

156

157

158

159

160

161

162

163

CHAPTER 10
NUCLEAR AND PARTICLE PHYSICS

10.1 BINDING ENERGY AND MASS DEFECT

LEARNING OUTCOMES

At the end of this chapter, students should be able to:
a) Define and use mass defect  m  [ Z mp  N mn ]  m

b) Define and use mass defect EB  mc 2

c) Determine binding energy per nucleon EB
d) Determine binding energy per nucleon

A

10.2 RADIOACTIVITY

LEARNING OUTCOMES

At the end of this chapter, students should be able to:

a) Explain α, β+, βˉ and γ decays

b) State decay law and use decay equation.

c) Define and determine activity, A and decay constant, 

d) Use = − or = − ln 2

e) Define and use half-life, 1 =
2

10.3 INTRODUCTION TO PARTICLES PHYSICS
LEARNING OUTCOMES
At the end of this chapter, students should be able to:

a) State the thermionic emission
b) Explain the acceleration of particle by electric and magnetic field
c) State the role of electric and magnetic field in particle accelerators (linac and

cyclotron) and detectors (general principles of ionization and deflection only)
d) State the need of high energy requires to investigate the structure of nucleon

e) Indicate the standard quark-lepton model particles (baryons, meson, leptons and

photon)

f) Explain the corresponding antiparticle for every particle

164

QUESTIONS

1. Nuclide that have binding energy per nucleon lie in the range of nucleon numbers
A. 1 to 20
B. 20 to 50
C. 50 to 80
D. 200 to 240

3. Find the composition of nucleus for nuclide and determine the mass defect of this
nuclide. Given the mass of :
(mass of a proton, m is 1.00728 u, a neutron, m is 1.00867 u,

pn

mass of nucleus is 62.913267u)

4. What is the binding energy per nucleon for 120
Sn

50

10.2 RADIOACTIVITY

5. What value of Z (atomic number) and A (mass number) result in the 23982U alpha decay?
A. Z = 92; A = 238
B. Z = 91; A = 238

C. Z = 90; A = 234
D. Z = 93; A = 238

6. Isotope 288U has a half-life of 4.5x109 years. Calculate the decay constant
A. 4.88x10-18 s-1
B. 4.88x10-8 s-1
C. 1.88x10-10 s-1
D. 1.88x10-18 s-1

5. Explain the general processes and characteristic of

(a)  decay

(b)  decay

(c)  decay

7. (a) Define:
i. Activity,
ii. Decay constant and
iii. Half-life.

(b) Why do gamma particles penetrate matter more easily than beta particles do?

8. (a) The half-life of 131I is 8 days. On a certain day, the activity of a 131I sample is 6.4 mCi.
What is its activity 40 days later?

(b) The half-life of 131I is 8.04 days. Three days after it was prepared, its activity was
0.50µCi. How many curies (in µCi) were initially prepared?

165

9. Huge amounts of radioactive 131 I were released in the accident at Chernobyl in 1986.
53

Chemically, iodine goes to the human thyroid. (Doctors can use it for diagnosis and treatment of

thyroid problems.) In a normal thyroid, 131 I absorption can cause damage to the thyroid.
53

(a) Write down the reactions for the decay of 131 I .
53

(b) Its half-life is 8.0 day; how long would it take for ingested 131 I to become 10% of the
53

initial value?

(c) Absorbing 1 mCi of 131 I can be harmful; what mass of iodine is this?
53

[Note : 1 curie = 1 Ci = 3.7 x 1010 decays per second or 1 Ci = 3.7 x 1010Bq]

10.3 INTRODUCTION TO PARTICLES PHYSICS

10. An antiproton is an atomic particle that has
A) the mass of a proton and the charge of an electron.
B) the mass of an electron and the charge of a proton.
C) the mass of a neutron and the charge of a proton.
D) the mass of a proton and the charge of a neutron.

11. Particles that participate in the strong nuclear interaction are called
A) neutrinos
B) hadrons
C) leptons
D) electrons

12. What do we call a particle that is not made up of any smaller particles?
A) Minimum particle
B) Elementary particle
C) Original particle
D) electrons

13. State Standard Model of particle physics

14. Give three factors of thermionic emission to occure

15. Often seen with the up quark, its partner in the "first generation of matter", the down quark is
slightly heavier and just as fun. In terms of e (the charge of a proton), what is the electric
charge of a down quark?

166