Note: these problems are a just an arbitrary smattering of the many types we have studied this semester. For a complete selection, refer to your text, projects, questions sheets, and notes.
1. A 5 m long water wave that travels at
200 m/s has what period?
2. An echo is heard 7 s after a sound is produced in 280C
air. Find the distance to the reflecting
surface.
3. A bird sings in a valley. The echo
from one wall reaches the bird in 2.5 s and the echo from
the second wall reaches
it 3.5 seconds later. If the Tair = 300C, find the width of
the valley.
4. When the Tair = -200C, an
echo is heard after 1.4 seconds. Find the distance to the reflecting
surface.
5. A car travelling at 25m/s toward an
intersection sounds its 320 Hz horn. If the Tair = -150C,
what frequencies would
a listener detect as the car approaches, passes, and retreats?
6. Trains S and B, on a collision course,
are travelling at 25m/s and 30m/s respectively. The Tair
= 250C when
Train S sounds its 500 Hz horn. What frequency will the engineer of Train
B
hear?
7. A car that is travelling at 18 m/s
toward a stationary observer sounds its 200 Hz horn. If the
Tair = 00C,
what frequencies are heard by the observer as the car approaches, passes
and
retreats?
8. A closed, 15 cm long, 2.5 cm diameter tube will resonate with a
tuning fork of what frequency
when the Tair = 150 C?
9. Find the length of an open, 2 cm diameter tube that resonates with
a 256 Hz tuning fork in
200C air.
10. a) A 250 Hz tuning fork and an open,
63 cm long, 4 cm diameter tube are sounded together.
If the Tair = 220 C, find the beat frequency.
b) Recalculate
the question for a closed, 16 cm long, 2 cm diameter tube.
11. Find the length of' an open tube,
diameter 1.5 cm, that will resonate with a 256Hz tuning fork
when the
Tair = 250C.
12. A 15 cm long, 1 cm diameter closed
tube produces a sound at the same time as a 33 cm long,
2 cm diameter
open tube. Find the resulting beat frequency.
13. A 100 cm long string tensioned at 90 N sounds at 150 Hz. Find the
string's frequency if it is
shortened to 50 cm and the tension reduced
to 10 N.
14. A 100 cm long, 1 mm diameter string
under a tension of 25 N sounds at 160 cps. Find the
new frequency
if the string is shortened to 25 cm and the tension increased to 36 N.
15. A 100 cm long, 0.44 cm diameter string
produced a frequency of 220 Hz. What frequency
would be
produced by an 80 cm long, 0.2 cm diameter string of the same material?
16. A 50 candela source and a 70 candela source are placed at opposite
ends of a meter stick.
Where must a screen be placed to show
equal illumination?
17. Find the illumination on a surface
3.5 m from an 18 candela source.
18. A 25 candela source 4.5 m away from a surface produced three times
the illumination of a
source of unknown intensity 9 m away
from the screen. Find the intensity of the unknown
source.
19. A 25 candela source produced an illumination of 3.5 lux on a surface.
Find the distance from
the source to the surface.
20. a) Diagram the formation of a real image in a curved mirror.
b) Diagram the two situations in which
a virtual image can be formed by a curved mirror.
Identify the
object and image in all three diagrams.
21. A 10 cm tall virtual image is formed 25 cm from a concave mirror,
f = 15 cm. Find the object
and its height.
22. Light moves from air (I.R.= 1) into crown glass (I.R.= 1.52) at
an angle of incidence of 250 .
Calculate the angle of refraction. Sketch
the path of the light ray.
23. Find the critical angle at the boundary of flint glass (IR = 1
61) and water (I.R.+l.33).
24. Sketch the path of a light ray moving from air through an equilateral
triangular flint glass
(I.R. = 1.61)and back into air. The
initial angle of incidence is 200.
25. A 10 cm tall object is placed 15 cm from a converging lens, f =
20 cm. Find the image height.
26. Find the magnification of a simple magnifier, f = 10 cm.
27. Sketch the formation of an image in a: a) converging lens b) diverging
lens. Identify the
principal focus, the object and the
image.
28. An f = 0.5 cm lens and an f = 25 cm lens are used to make a microscope
and a telescope. If
the lenses can be placed 20 cm apart,
calculate the magnification of each device. In each case,
which lens will be used as the objective
and which as the eyepiece?
29. A 6.0 x 10-4 C charge and a -5.0 x 10-5 C
charge are separate by 25 cm of air. Recalling that
K = 9 x
10 Nm2 / C2, find the force between the two
charges.
30. A 3 N force acts on a 500 microcoulomb charge in air. Find the
electric field at that point.
31. The charge of an electron or proton is 1.60 x 10-l9
C. Find the force acting on them when they
are separated by 1 * 10-12
m.
32. 15 amperes flows through a light bulb that is connected to a 120
V source. Find the power
rating and resistance of the bulb.
33. Resistances of 5, 8 and 10 ohms are connected in series to a 9
V source. Diagram the circuit
and find the potential fall across each
resistor and the current passing through each resistor.
34. A 7.5 * 10-5 Tesla magnetic
induction would occur in the portion of a magnetic force field
how far
from a wire carrying a 45 A current?
35. What is the current flowing through
a 3.3 m diameter hoop if the magnetic induction at its
center is 5.5
* 10-2 Wb/m2?
36. A magnetic force field pushes with
8.8 N against a 0.9 m long wire carrying 25 A of current.
What is the magnetic
flux density at that point in the field?
37. Two 2.2 m long wires 0.3 m apart from
each other push at each other with 3.2 N. If one wire
carries
2.6 A of current, what current is flowing through the other wire?
38. A galvanometer has a coil resistance
of 100 ohms and is fully deflected by a 920 mA current.
A resistor
of what size will allow it to function as a voltmeter reading a maximum
of 400 V?
39. A galvanometer with a coil resistance
of 7 ohms can read a maximum potential of 17 mV.
What resistor
is used to reconfigure it as a maximum reading 17 A ammeter?
40. a) A device using 400 W of power in
6.5 minutes has what kilowatt - hour rating?
b) If Joules
= KW x seconds, what is its energy usage in Joules?
41. What EMF is created by a 0.8 m long
wire moving at 6 m/s through a section of a magnetic
field with
a magnetic induction of 7 * 10-3 Tesla?
42. A transformer has 4 primary coil and
7 secondary coil turns.
a) A 20
A primary current becomes what secondary current?
b) A 12
V secondary potential was what primary potential?
c) What
are the input and output powers?
Optional: Refer to the appropriate sections of your text or other reference
text.
43. Find the intensity of the following
sounds. a) 120dB b) 50dB c) 50dB d) 55dB e) 65dB
44. Find the intensity level, in w/m2,
of the following sounds.
a) 10-8
b) 10-4 c) 102 d) 5x10-3 e) 4.5x10-7