EP025 Buku Tutorial 20222023

INTERFERENCE OF REFLECTED LIGHT IN THIN FILMS
8. Identify the occurrence of phase change upon reflection.

*from lower to higher refractive index, phase change = π rad or path difference = ½ λ
10. Describe with the aid of a diagram the interference of light in thin films at normal

incidence.
*limited to three media
11. Use the following equations for reflected light with no phase difference (non
reflective coating):

i. Constructive interference: 2nt = mλ

ii. Destructive interference: 2nt =  m + 1 
 2

12. Use the following equations for reflected light of phase difference π rad (reflective
coating):

i. Constructive interference: 2nt =  m + 1 
 2

ii. Destructive interference, 2nt = mλ, where m = 0, ±1, ±2, ±3, …
13. Explain the application of thin films (e.g.: solar panel, glass tint).

DIFFRACTION BY A SINGLE SLIT

14. Define diffraction.

15. Explain with the aid of a diagram the diffraction of a single slit.

16. Use:

i. = for dark fringes (minima)


ii. = ( +12) for bright fringes (maxima), where m = ±1, ±2, ±3,...



*dark fringes: m = 1, 1st dark or 1st order min, m = 2, 2nd dark or 2nd order min

bright fringes: m = 1, 1st bright or 1st order max, m = 2, 2nd bright or 2nd order max

central bright: use equation for first dark

DIFFRACTION GRATING
17. Explain with the aid of a diagram the formation of diffraction.
18. Apply d sin θm = mλ where d = 1/N (e.g: transparent compact disc, muslin cloth).

*bright fringes: m = 0, central or 0th order max, m = 1, first bright or 1st order max
N: number of slits per unit length

43

KOLEJ MATRIKULASI KEJURUTERAAN JOHOR
KEMENTERIAN PENDIDIKAN MALAYSIA

TUTORIAL 7
(PHYSICAL OPTICS)

SECTION A

1. Bright spots on the interference pattern are visible because of ___

A Destructive interference of light
B Constructive interference
C Polarization of light
D Light is always bright

2. Two lights are in phase. They will interfere constructively with maximum
amplitude if the path difference between them is ___

A one-half wavelength
B one-quarter wavelength
C one-eight wavelength
D one wavelength

3. What is meant by two coherent light sources?

A Two coherent light sources mean two sources of light which have the same
wavelength and frequency AND a non-constant phase difference between
them.

B Two coherent light sources mean two sources of light which have the same
wavelength and frequency AND a constant phase difference between them.

C Two coherent light sources mean two sources of light which have the same
wavelength and frequency AND a constant path difference between them.

D Two coherent light sources mean two sources of light which have a constant
phase difference between them.

4. Which of the following characteristics is NOT the conditions for the formation of
a permanent interference pattern of two light waves?

A Same amplitude
B Same frequency
C Constant phase difference
D Propagate in the same direction

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5. On a rainy day, a small oil film on water shows brilliant colours. This is due to __
A interference of light
B scattering of light
C absorption of light
D dispersion of light

6. Define wavefront:
A All particles have opposite phase of vibration
B Few particles are in same phase, rest are in opposite phase
C All particles in the wave have same phase
D None of these

7. Which of the following will increase the spacing of Young’s double slit fringes?
A A blue light is used instead of a red light
B The screen is moved closer to the slits
C The slits are moved closer together
D Each slit is made wider

8. A colourful pattern is observed on a soap bubble. These phenomenon is caused by
A the diffraction of light
B the diffraction and refraction of light
C the diffraction and reflection of light
D the reflection and interference of light

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SECTION B

DOUBLE SLITS

1. a) Explain Huygen’s principle with the aid of a diagram.
b) State the difference between interference and diffraction.

2. A flat observation screen is placed at a distance 1.5 m from a pair of slits. The
separation on the screen between the central bright fringe and the first-order bright
fringe is 0.035 m. The light illuminating the slits has a wavelength of 540 nm.
Determine the slit separation.
(Ans: 2.31 x 10-5m)

3. In a Young’s double-slit experiment, the separation, ym between the second-order
bright fringe and the central bright fringe on a flat screen is 0.016 m when the light
has a wavelength of 405 nm. Find the separation ym when the light has a wavelength
of 560 nm.
(Ans: 0.022 m)

4. Monochromatic light of wavelength 500 nm passes through a double slit produces 50th
dark fringe a point on a screen. What should be the wavelength to produce 36th dark
fringe at the same point?
(Ans:689 nm)

5. In a double slit experiment where the slit separation is 0.1 mm and the screen is 20 cm
away from the slits. The distance between 5th and 7th bright fringes was observed as

2.56 mm. What is the wavelength of the light used?
(Ans:640 nm)

6. Two narrow slits are illuminated by light consisting of two wavelengths 600 nm and
unknown. The second dark fringe of 600 nm light is formed at the same position as the
third order bright fringe of the other light. Determine the unknown wavelength.

(Ans:300 nm)

7. In a Young’s double slit experiment the screen is placed at 1.6 m from the screen and a
monochromatic light 589 nm was used. If the distance of the 4th bright fringe is 1.6 mm
from the centre, calculate the slit separation.
(Ans:2.36 mm)

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THIN FILMS

8. With the aid of a diagram, describe the phase change when the light pass through
reflective and non-reflective coating of thin film.

9. Find the thickness of an optical coating MgF2 with refractive index 1.35 in order to
eliminate reflected light of wavelength 550 nm (in air) when incident on a lens of
refractive index of 1.50.

(Ans:101.85 nm)

10. A mix of red light of ( red = 661 nm) and green light ( green = 551 nm) is directed
perpendicularly onto a soap film of refractive index 1.35 that has an air on either side.
What is the minimum nonzero thickness of the film, so that destructive interference
causes it to look red in the reflected light?
(Ans:204 nm)

11. Light of wavelength 556 nm is incident perpendicularly on a soap film of refractive
index in air. If the refractive index of soap film is 1.35, what are the two smallest non-
zero thickness (in nm) for which the reflected light undergoes constructive interference?
(Ans:103 nm, 308 nm)

12. A thin film (refractive index between 1.00 and 1.40) floats on an open tank of oil with
refractive index, n = 1.40. When the light has a wavelength of 642 nm (0n air) shines
perpendicularly down through the air onto the thin film, it looks bright due to
interference of reflected light by the film and oil surfaces. If the thickness of the thin film
is 280nm, what is the refractive index of the thin film?
(Ans:1.15)

13. A uniform layer of water (n = 1.33) lies on a glass plate (n =1.52), it appears bright
when light of wavelength 432 nm shines perpendicularly on the layer. Determine the
minimum thickness of the film.
(Ans:162 nm)

14. A soap bubble (n = 1.33) having a wall thickness of 120 nm is floating in air.

(a) What is the wavelength of the visible light that is most strongly reflected?
(b) Find the two smallest film thickness larger than the one given that can produce

strongly reflected light of this same wavelength.
(Ans:640 nm; 360 nm; 602 nm)

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SINGLE SLIT

15. Explain the formation of single slit pattern by using Huygen’s principle.

16.

(a) A laser beam of wavelength 625 nm illuminates a single slit width 5.7 x 10-4 m.

What is the angular width of the central maximum? (Ans: 0.1260 )

(b) What will happen to the diffraction patter in (a) if the size of the slit is decreased.

17. Light that has a wavelength of 642 nm passes through a slit 4.32 x 10-6 m wide and

falls on a screen that is 1.5 m away. What is the distance on the screen from the centre

of the central bright fringe to the third dark fringe on either side?
(Ans: 66.9 cm @ 0.69 m)

18. Light with a wavelength of 520 nm (in vacuum) shines through a small slit produces

a diffraction pattern with its central bright fringe 30 mm wide when viewed on a flat

screen 0.6 m away from the slit. What is the width of the slit?
(Ans: 2.08 x 10-5 m)

19. A beam of monochromatic light is diffracted by a slit of width 0.600 mm. The

diffraction pattern forms on a wall 1.3 m beyond the slit. The width of the central

maximum is 2.00 mm. Calculate the wavelength of the light.
(Ans: 461 nm)

20. A single slit diffraction pattern is obtained on a screen placed at a distance of 10 cm
from the slit width 5 µm. The wavelength of the monochromatic light used is

5.9 x 10-7 m.
(a) Calculate the angular separation between the first and second minima.
(b) What is the width of the central bright fringe?
(c) How many dark fringes are found on the screen?
(Ans: 6.870, 2.38 cm, 16)

21. Light of wavelength 587.5 nm illuminates a slit of width 0.75 mm.

(a)At what distance from the slit should a screen be placed if the first minimum

in the diffraction pattern is to be 0.85 mm from the central maximum?

(b) Calculate the width of the central maximum.
(Ans: 1.09m, 1.7 mm)

22. Light of wavelength 600 nm falls on a 0.40 mm wide slit and forms a diffraction

pattern on a screen 1.5 m away.

(a) Find the position of the first dark band on each side of the central maximum.

(b) Find the width of the central maximum. (Ans: 4.5 mm, 2.3 mm)

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DIFFRACTION GRATING

23. (a) Explain briefly the formation of diffraction pattern by a diffraction grating.
(b) A monochromatic light of wavelength 5.49 x 10-7 m is incident normally on a
diffraction grating. If a diffraction pattern of the first order is observed at an angle
280 from the normal, what is the number of lines per mm on the diffraction grating?
(Ans:855 lines/mm)

24. Monochromatic light of wavelength 600 nm is incident on a diffraction grating which
has 7.3 x 105 lines per meter.
(a) Calculate the maximum number of orders that can be observed.(Ans :n = 2)
(b) How to maximize the number of orders?

25. Monochromatic light from a helium-neon laser of wavelength 633 nm is incident
normal to the diffraction grating. If the grating consists of 5000 lines per cm, calculate
the angle at which second order maximum can be observed.
(Ans: 39.30 )

26. White light is spread out into its spectral components by a diffraction grating. If the
grating has 2000 lines per centimeter, at what angle does red light of wavelength 640
nm appear in the first order spectrum?
(Ans: 7.350 )

27. Light of wavelength 500 nm is incident normally on a diffraction grating. If the third-
order maximum of the diffraction pattern is observed at 320.
(a) What is the number of rulings per centimeter for the grating?
(b) Determine the total number of maxima that can be observed in this situation.
(Ans: 3533 line/cm, 11)

28. A diffraction grating that has a 4500 lines per cm produces a second order maximum
at an angle 420 with respect to the central maximum. What is the wavelength of
monochromatic light used?
(Ans: 743 nm)

29. Light containing two different wavelengths passes through a diffraction grating
with 1200 slits/cm. On a screen 15.0 cm from the grating, the third-order maximum of
the shorter wavelength falls midway between the central maximum and the first side
maximum for the longer wavelength. If the neighboring maxima of the longer
wavelength are 8.44 mm apart on the screen, what are the wavelengths in the light?
(Hint: Use the small angle approximation.)

(Ans: 78.1 nm and 469 nm)

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TOPIC 8 : WAVE PROPERTIES OF PARTICLE
8.1 de Broglie Wavelength
8.2 Electron Diffraction
At the end of this topic, students should be able to:
DE BROGLIE WAVELENGTH
1. State wave-particle duality.
2. Use de Broglie wavelength, = ℎ



ELECTRON DIFFRACTION
3. Describe the observations of electron diffraction in Davisson-Germer experiment.
4. Explain the wave behaviour of electron in an electron microscope.

*relate de Broglie wavelength of electron with the resolving power of the microscope.
5. State the advantages of electron microscope compared to optical microscope.

50

KOLEJ MATRIKULASI KEJURUTERAAN JOHOR
KEMENTERIAN PENDIDIKAN MALAYSIA

TUTORIAL 8
(WAVE PROPERTIES OF PARTICLE)

SECTION A

1. What is wave-particle duality?
A. The idea that light behaves both as a particle and a wave.
B. The idea that light behaves like a particle.
C. The idea that light behaves like a wave.
D. The idea that light behaves as a particle one day, and a wave the next.

2. What is a photon?
A. A discrete packet of energy -- the particle form of light.
B. A light wave.
C. A type of electron.
D. An energy particle.

SECTION B

1. Find the de Broglie wavelength of a thermal neutron of mass 1.67 x 10-27 kg

travelling at a speed of 2200 ms-1. (ANS: 0.18 nm)

2. What is the de Broglie wavelength for a particle moving with speed 2x106 ms-1 if the
particle is:
(a) electron
(b) proton
(c) a 0.2 kg ball
(ANS: 3.6 x 10-10 m; 2 x 10-13 m; 1.65 x 10-39 m)

3. A proton is accelerated to a potential difference of 1000 V. What is its de Broglie

wavelength? (ANS: 9.1 x 10-13 m)

4. If the de Broglie wavelength is 1 x 10-10 m, what are its velocity and its kinetic

energy (in eV)? (ANS: 7.28 x 106 ms-1; 151 eV)

5. State the advantages of electron microscope compared to optical microscope.

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TOPIC 9 : NUCLEAR AND PARTICLE PHYSICS

9.1 Binding Energy and Mass Defect
9.2 Radioactivity
9.3 Particle Accelerator
9.4 Fundamental Particle

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

BINDING ENERGY AND MASS DEFECT
1. Define and use mass defect, Δ = ( + ) −
2. Define and use binding energy, = Δ 2
3. Determine binding energy per nucleon,



4. Sketch and describe graph of binding energy per nucleon against nucleon number.

RADIOACTIVITY

5. Explain , +, − and decays.

*radioactive decay as spontaneous and random process

**introduce neutrino and antineutrino

6. State and use decay law = −



7. Define and determine activity, A and decay constant,

*consider decay curve

8. Use = 0 − or = 0 −

9. Define and use half-life, 1/2 = ln 2


PARTICLE ACCELERATOR
10. State the thermionic emission.
11. Explain the acceleration of particle by electric and magnetic field.
12. State the role of electric and magnetic field in particle accelerators (linac and

cyclotron) and detectors (general principles of ionisation and deflection only).
13. State the need of high energies required to investigate the structure of nucleon.

FUNDAMENTAL PARTICLE
14. Explain the standard quark-lepton model particles (baryons, meson, leptons and

hadrons).
15. Explain the corresponding antiparticle for every particle.

52

KOLEJ MATRIKULASI KEJURUTERAAN JOHOR
KEMENTERIAN PENDIDIKAN MALAYSIA

TUTORIAL 9
(NUCLEAR AND PARTICLE PHYSICS)

SECTION A

1. How many protons are there in a nucleus of the isotope of Rubidium, 3857
A. 85
B. 122
C. 37
D. 48

2. Which isotope below has the highest nuclear binding energy per gram? No
calculation is necessary.
A. 4He
B. 16O
C. 32S
D. 55Mn

3. Which of the following statements is incorrect?
A. Mass defect is the amount of matter that would be converted into energy if a
nucleus were formed from initially separated protons and neutrons.
B. Nuclear binding energy is the energy released in the formation of an atom
from subatomic particles.
C. Nuclei with highest binding energies are the most stable nuclei.
D. Einstein postulated the Theory of Relativity in which he stated that matter and
energy are equivalent.
E. Mass number is the sum of all protons and electrons in an atom.

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4.

Number of
undecayed nuclei

FIGURE 1 Time

The reduction in the number of remaining nuclei in a radioactive sample is shown
in FIGURE 1. Which graph shows the relationship between the number of
remaining nuclei, N and the activity of the sample, A?

A
A

A N N
C.
A
A

B N D. N

5. The _____ of particle physics is a mathematical description of the fundamental (or
elementary) particles in the universe, and the forces by which they interact with
each other.
A. Quark model
B. Standard model
C. Progressive model
D. Electron model

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6. Which of the following particles is an example of a quark?
A. Charm
B. Electron
C. Gluon
D. Muon neutrino

7. How many regular particles are there in the standard model (not counting
exchange particles, the Higgs boson, or anti-particles)?
A. 6
B. 29
C. 12
D. 24

SECTION B

1. FIGURE 1 shows the identity of sodium (natrium) atom based on the periodic
table.

11
Na
22.98977

FIGURE 1
Determine

a. the number of proton and electron of sodium atom.
b. the number of nucleons of sodium atom.
c. the number of neutrons of sodium atom.
d. the charge of sodium nucleus

(ANS: 11;11; 23; 12; +1.76x10-18 C)
2. Based on question 1, determine

a. the total mass of proton of sodium atom (in kg and u).
b. the total mass of neutron of sodium atom (in kg and u).
c. the total mass of electron of sodium atom (in kg and u).

(ANS: 1.8399x10-26 kg; 11.0800 u; 2.0099x10-26 kg; 12.1040 u; 1.0020x10-29 kg;
6.0344x10-3 u)

3. Based on question 1 and question 2, determine:
a. the mass defect of sodium nucleus (in kg and u).
b. the binding energy of sodium nucleus (in Joule and eV).

55

c. the average binding energy (binding energy per nucleon) of sodium
nucleus (in Joule and eV).

(ANS: 3.3254x10-28 kg; 0.2003 u; 2.9929x10-11 J; 186.541MeV; 1.3013x10-12 J;
8.1105MeV)

4. FIGURE 2 shows the identity of uranium atom based on periodic table.

92
U
238.0289

FIGURE 2
Determine:

a. the number of proton and electron of uranium atom.
b. the number of nucleons of uranium atom.
c. the number of neutrons of uranium atom.

(ANS: 92;92; 238; 146)

5. Based on question 4, determine:
a. the total mass of uranium nucleon (in kg and u).
b. the mass defect of uranium nucleus (in kg and u).
c. the binding energy of uranium nucleus (in Joule and eV).
d. the average binding energy (binding energy per nucleon) of uranium
nucleus (in Joule and eV).
(ANS: 3.9517x10-25 kg; 237.9784 u;3.2482x10-27 kg; 1.9561 u; 2.9234x10-10 J;
1822.095 MeV; 1.2283x10-12 J; 7.66MeV)

6. By comparing the binding energy and the average binding energy between sodium
and uranium, which nucleus is more stable? Justify your answer. (Sketch binding
energy per nucleon against nucleon graph and mark the position)

7. Explain the general processes and characteristic of:

a.  decay
b.  decay
c.  decay

56

8. Thorium-234 has a half-life of 24 days. The initial activity of a sample of thorium-
234 is 8.0 ×104 Bq,
a. Calculate the activity of the sample after 72 days?
b. How long does the sample take for its activity to become 3.0 × 104 Bq?
(ANS: 1.0 x 104 Bq; 34.1 days)

9. Radium-266 is found to have a decay constant of 1.36 × 10-11 Bq. Given that Curies
had roughly 200 g of radium in 1898. Determine its,
a. half-life in years
b. mass remain 100 years later?
(ANS: 1.62 x 103 y; 192 g)

10. The radioactive isotope 198 Au has a half-life of 64.8 hours. A sample containing this
isotope has an initial activity (t = 0) of 40.0 μCi. Calculate the number of nuclei that
decay in the time interval between t1= 10.0 hours and t2 = 12.0 hours.
(1μCi = 3.7×104 decay/s)
(ANS: 9.47 x 109 nuclei)

11. A radioactive source contains 1.0 × 10-4 g of uranium-238 and its average rate of

decay is 1.2 s-1. The safety limit of radioactive activity is 10 μCi.

a. Calculate the maximum mass of uranium-238 which may be used without

shielding. (ANS: 31 g)

b. It is suggested that some radioactive waste could be stored underground in

metal containers and would not cause damage to environment. Give

comments.

12. A sample of radioactive isotope I131 is used for medical diagnosis of the kidneys.

53

The isotope has a half-life of 8.0 days and the sample is required to have an activity

of 8.0 × 105 s-1 at the time it is given to the patient. Calculate the mass of the I -131

present in the sample

a. at the time it is given

b. when it is prepared 24 hours earlier

c. 24 hours after being given

(ANS: 1.74 x 10-10 g; 1.9 x 10-10 g; 1.6 x 10-10 g)

57

13.

FIGURE 3
FIGURE 3 shows the variation of the activity of a radon sample with time. The
sample was in a tube and initially there were 5.0 × 109 radioactive radon atoms
when the tube was inserted into the body of a patient. To provide enough dosage
for the therapy, the tube was removed after 6 days. From the graph,

a. find the half-life radon
b. determine the number of α-particles emitted by the sample in 6 days
c. If the sample were inserted into the patient’s body one day after been

prepared, how long should it be left in the body in order to provide for
the dosage required as in (b)

(ANS: 4 days; 3.23 x 109; 8.45 days)
14. What are the particle of protons are made of?
15. What are the particle of electrons are made of?
16. Which of the following are made of quarks?

a. Baryons
b. Mesons
c. Muon neutrino

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