9322

THE UNIVERSITY OF SYDNEY

FACULTY OF SCIENCE

INTERMEDIATE PHYSICS

PHYS 2011 PHYSICS 2A

JUNE 2008 TIME ALLOWED: 2 HOURS

ALL QUESTIONS HAVE THE VALUE SHOWN

INSTRUCTIONS:

This paper consists of 2 sections.

Section A Optics 50 marks

Section B Nuclear Physics 40 marks

Candidates should attempt all questions.

USE A SEPARATE ANSWER BOOK FOR EACH SECTION.

In answering the questions in this paper, it is particularly important to give rea-

sons for your answer. Only partial marks will be awarded for correct answers

with inadequate reasons.

No written material of any kind may be taken into the examination room. Calcu-

lators are permitted.

9322 Semester 1 2008 Page 2 of 10

Table of constants

Avogadro’s number NA=6.022 ×1023 mole−1

speed of light c=2.998 ×108m.s−1

electronic charge e=1.602 ×10−19 C

electron rest mass me=9.110 ×10−31 kg

electron rest energy mec2= 511 keV

electron volt 1 eV = 1.602 ×10−19 J

proton rest mass mp=1.673 ×10−27 kg

neutron rest mass mn=1.675 ×10−27 kg

Planck’s constant h=6.626 ×10−34 J.s

Planck’s constant (reduced) ¯h=1.055 ×10−34 J.s

Boltzmann’s constant kB=1.380 ×10−23 J.K−1

Universal gas constant R=8.315 J.mol−1K−1

Stefan’s constant σ=5.670 ×10−8W.m−2.K−4

permittivity of free space ε0=8.854 ×10−12 C2.N−1.m−2

gravitational constant G=6.673 ×10−11 N.m2.kg−2

atomic mass constant u=1.660 ×10−27 kg

degrees/radian 180/π '57.2958

9322 Semester 1 2008 Page 3 of 10

SECTION A

OPTICS

FORMULAS

n=c/v v =fλ

nasin θa=nbsin θb

Iav =1

20cE2

max

dsin θ=mλ

dsin θ= (m+1

2)λ

E2

tot =E2

1+E2

2+ 2E1E2cos(φ2−φ1)

I=I0cos2 πd sin θ

λ!

β=2πa sin θ

λ

I=I0

sin(β/2)

(β/2)

2

sin θ=mλ

a

φ=2πd sin θ

λ

I=I0cos2(φ/2)

sin(β/2)

(β/2)

2

`=λ2

∆λ

I=I0

sin(β/2)

(β/2)

2

sin(Nφ/2)

sin(φ/2)

2

sin θ−sin θi=mλ

dsin θ=mλ

d

R=λ

∆λ

R=mN

9322 Semester 1 2008 Page 4 of 10

Itrans =Iincid cos2φ

tan θp=nb

na

∆θ=1.22λ

D

∆φ= 2π 2n2t

λvac !+φ12 +φ23

∆φ= 2π 2n2tcos θ2

λvac !+φ12 +φ23

It

Ii

=1

1 + Fsin2(δ/2) where δ= 2π 2tcos θ

λ!

F=4R

(1 − R)2

F=π√F

2

2tcos θ=mλ

R=mπ

2√F

∆λF SR =λ

m'λ2

2t