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PHY222 Exam
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Each question is worth 3 marks. Answers should be rounded to the correct number of significant digits.
F  q0 E
v
F

 f 
m L
T
  t x 
y  A sin 2   
  T  
  10 dB log I I O 
I 2 I 1  r1 r2 
2
v 2 v1  T2 T1
 1  vO v 

f O  f S 
 1  vS v 
sin   1.22
2 L  n

D
2 L  n  2 n odd
f beat  f 2  f 1
EPE  q 0 V  W
F
E
k q1 q 2
r2
kq
r2
EPE 
kq1 q 2
r
kq
r
q
 V
E




d
A

V 
V  Vref  Ex
Φ E   E cos  A  Q 

1
2
mv 2f  qV f  12 mv02  qV0
x  v 0 t  12 at 2
V  IR
P  IV
2
2
u

E  B
L
E  cB
A
S  P A  uc
   0 1   T  T0 
E  hf  hc 
R  R1  R2  
A   log T  
c
1
1
1



y

sin   m  m
R R1 R2
L
W
  MB sin 
ym

sin  
m
M  NIA
L
d
8
0 I
c  3.00  10 m s
B
2 r
h  6.626  10 34 J  s
 I
k  8.99  10 9 Nm 2 C 2
BN 0
2R
12

C 2 Nm 2
  8.85  10
B   0 nI
   4  10 7 Tm A
F  q vB sin 
R
F  ILB sin 
0C  273.15 K
1 eV  1.602  10 19 J
mv 2
F
r
1. A certain wave has a frequency of 20.0 kHz. Write an equation for the wave if:
a) It is a sound wave in air at 0.0°C (v = 331 m/s, A = 1.5 cm).
b) It is a sound wave in air at 40.0°C (A = 1.5 cm).
c) It is a wave on a 2.5 g/m string with a tension of 250 N (A = 1.5 cm).
d) It is the electric field of a radio wave in air (Bmax = 2.8 × 10-5 T).
v  v 0  at
2. Two speakers are 4.0 m apart creating in-phase, equal-intensity 85 Hz tones. The speed of sound is
340 m/s. At a location 1.0 m from one speaker and 3.0 m from the other:
a) Are the sound waves completely in phase, partially out of phase, or completely out of phase?
b) By how many decibels does the intensity from the closer speaker exceed that from the farther one?
c) Do you expect the waves to completely cancel out, partially cancel, or reinforce each other? Why?
3. Find the total of all forces the on a 2.5 g object traveling east at 35 m/s with a charge of 1.4 mC. There
is a 1.5 C charge 18 m directly ahead and a 0.50 T magnetic field pointing north.
4. Use Gauss’ law to find the electric field 3.2 m from a long line with a uniform charge density of
3.7 C/m. Indicate the dimensions of the Gaussian surface as well as the flux through each of its parts.
5. A 2.6 C charge is fixed in place. A 3.4 C charge with a mass of 4.5 mg is held 5.0 cm away and then
released. How far is it from the fixed charge when its speed reaches 470 m/s?
PHY222 Exam (Page 2)
Each question is worth 4 marks. Answers should be rounded to the correct number of significant digits.
F  q0 E
v
F

 f 
m L
T
  t x 
y  A sin 2   
  T  
  10 dB log I I O 
I 2 I 1  r1 r2 
2
v 2 v1  T2 T1
2 L  n

E
k q1 q 2
r2
kq
r2
EPE 
kq1 q 2
r
kq
r
q
 V
E




d
A

V  Vref  Ex
D
Φ E   E cos  A  Q 

2 L  n  2 n odd
f beat  f 2  f 1
F
V 
 1  vO v 

f O  f S 
 1  vS v 
sin   1.22
EPE  q 0 V  W
1
2
mv 2f  qV f  12 mv02  qV0
V  IR
P  IV
2
2
u

E  B
L
E  cB
A
S  P A  uc
   0 1   T  T0 
E  hf  hc 
R  R1  R2  
A   log T  
c
1
1
1



y

sin   m  m
R R1 R2
L
W
  MB sin 
ym

sin  
m
M  NIA
L
d
8
0 I
c  3.00  10 m s
B
2 r
h  6.626  10 34 J  s
 I
k  8.99  10 9 Nm 2 C 2
BN 0
2R
12

C 2 Nm 2
  8.85  10
B   0 nI
   4  10 7 Tm A
F  q vB sin 
R
x  v 0 t  12 at 2
F  ILB sin 
v  v 0  at
mv 2
F
r
0C  273.15 K
1 eV  1.602  10 19 J
6. Each battery has a voltage of 1.5 V and each resistor has a resistance
of 5.0 . Find the current through the resistor marked with the
asterisk *.
7. The battery has a voltage of 24 V and the loop has a
radius of 2.0 cm, a temperature coefficient of resistivity of –0.0025/C°, and a resistance
of 5.0  at 15°C. What would be the magnitude and direction of the magnetic field at the
centre of the loop at 79°C?
8. How many times its own wavelength must a 1.9 eV photon travel to cover a distance of 2.5 light-years
through space?
9. An electromagnetic wave with an electric field of 1200 N/C is incident on a 3.0 cm layer of solution
containing 3.2 × 10-6 mol/L of a material with a molar absorptivity of 2.3 × 104 L/(mol cm). What is
the electric field of the transmitted wave?
10. A 750 Hz sound wave has a diffraction angle of 35° when passing through a certain circular opening.
What is the frequency of a microwave that has a diffraction angle of 3.5° when passing through a slit
whose width is the same as the radius of the circular opening? The speed of sound is 340 m/s.