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### 1. What do the direction of forces between opposite charges look like? +-34. What does amplitude measure in a wave? How much energy it carries. – PowerPoint PPT presentation

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Title: 1. What do the direction of forces between opposite charges look like?

1
• 1. What do the direction of forces between
opposite charges look like?

2
• 2. When you move two nuclei closer together, what
happens to the force of repulsion between them?
• The closer they get, the stronger the repulsive
force.

3
• 3. Why do strands of hair move towards the comb
after you comb your hair?

The hair gave up electrons to the comb, so it has
a positive charge, while the comb has a negative
charge. Opposite charges attract.
4
• 4. When you bring two charged balloons closer to
each other, what happens to the forces between
them and what do they do?

The closer the balloons get, the stronger the
forces. Since the balloons have the same charge,
they repel
5
• 5. Label the positive and negative charges in the
picture.

-
6
• 6. Why are metals good conductors?

They have loosely held electrons.
7
• 7. What causes an electric current?

Movement of electrons.
8
• 8. What is an insulator?

Some thing that resists the movement of electrons
or heat.
9
• 9. How can you increase the current across a
resistor?

Increase the voltage or decrease the resistance.
10
• 10. If you have batteries in series, and one
battery goes dead, what will happen to the
current?

The circuit is broken, so there is no current.
11
• 11. If you have batteries in parallel, and one
battery goes dead, what will happen to the
current?

Nothing, each battery has a separate path.
12
• 12. Label the circuits as series or parallel.

Parallel
Series
Series
Series
13
• 13. In a series circuit, what happens to the
brightness if you add another lamp?

The lamps get dimmer because the voltage is dived
between the lamps.
14
• 14. In a parallel circuit, what happens to the
brightness if you add another lamp?

Nothing, each lamp has a separate path to the
battery, so each has the same voltage.
15
• 15. In a series circuit, what happens if a lamp
burns out?

The circuit is broken, so all the lights go out.
16
• 16. In a parallel circuit, what happens if a lamp
burns out?

Only that light goes out.
17
• 17. What is true about the voltage in each branch
of a parallel circuit?

They are the same.
18
• 18. If you have a 2 ohm and a 4 ohm resistor in
parallel with a 12 volt battery, what is the
current in the circuit?

VIR so I V/R, R 1/(1/21/4)1.33 ohm 12 v
/ 1.33 ohm 9 amps.
19
• 19. If you have a 10 ohm, 15 ohm and 30 ohm
resistor in series, what voltage will produce a 1
amp current?

V IR so add the resistors together. V 55 ohms
times 1 55 v
20
• 20. What device can increase or decrease voltage?

A transformer can increase or decrease the
voltage.
21
• 21. Where is a magnetic field the strongest?

At the poles.
22
• 22. When two objects of different temperature are
placed together, what happens to the internal
energy of both?

The warmer object transfers heat to the cooler
object until both are at the same temperature.
23
• 23. What is the freezing point of water in
Kelvin?

Since Kelvin is oC plus 273, 0 oC is 273 Kelvin.
24
• 24. What is the boiling point of water in Kelvin?

Since Kelvin is oC plus 273, 100 oC is 373 Kelvin.
25
• 25. If 100 grams of water at 40 oC is mixed with
100 grams of water at 20 oC what will be the
final Temperature of the water?

Since the mass of both water samples is the same,
we can average the temperatures. 40 oC 20 oC
60 oC, 60 / 2 30 oC
26
• 26. Which solid has the highest specific heat ?

A, since the temp changes the least with the
27
• 27. Which way does heat flow?

From hot to cold.
28
• 28. What do the laws of Thermodynamics tell us
about energy and entropy?

That the Universe tends to move towards more
disorder (randomness)and less useful energy.
29
• 29. Which phase has the most entropy?

Gas, since the molecules are spread randomly.
30
• 30. Which phase has the least entropy?

Solid, since the molecules are arranged in a
pattern.
31
• 31. How much heat has to be added to the
substance to change it from a solid to a liquid?

From 40kJ to 80kJ, so 40kJ added.
32
• 32. What does a wave carry?

Energy, the matter only moves in circles.
33
• 33. What is the frequency of a wave with a
velocity of 10 m/s and a wavelength of 2 meters?

V ? x f So f v/ ? 10 m/s/2 m 5/sec or 5
Hertz
34
• 34. What does amplitude measure in a wave?

How much energy it carries.
35
• 35. A disturbance that only sends one wave is
called a .

A pulse.
36
• 36. If you are 1000 meters from a noise, how long
until you hear it? (use 340 m/s for speed of
sound)

Vd/t so t d/t 1000m/ 340 m/s 2.94 sec
37
• 37. Which part of the EM spectrum has the
shortest wavelength? Gamma

Gamma,
38
• 38. Which part of the EM spectrum has the longest

39
• 39. As a longitudinal wave passes through a
medium, how do the particles of the medium move?

Parallel to the direction of the energy.
40
• 40. Circle the part of the graph that shows the
loudest sound.

41
• 41. Put an x on the part of the graph that shows
the quietest sound.

42
• 42. How does the speed of a radio wave compare to
the speed of sound?
• Speed of light 300,000,000 m/s compared to speed
of sound 340 m/s.

Many times faster.
43
• 43. What does the angle of reflection equal?

The angle of incidence.
44
• 44. What happens to the pitch of the sound from
an object moving away from you?

It gets lower since it takes longer for each wave
to reach you.
45
• 45. What happens to the pitch of the sound from
an object moving towards you?

It gets higher since each wave gets to you faster
than the one before.
46
• 46. What is it called when waves spread out after
passing through a hole in a barrier?

Difraction.
47
• 47. Light exhibits the properties of both..

Waves and particles.
48
• 48. Which color has the shortest wavelength?

Violet
49
• 49. Which color has the longest wavelength?

Red
50
• 50. A convex lens produces a (virtual/real)
image.

Lens that converges (brings together) light rays.
Forms real images and virtual images depending
on position of the object. In a real image the
light rays intersect at the image location.
51
• 51. A concave lens produces a (virtual/real)
image.

Virtual, recall that a virtual image means no
light rays reach the image location.
52
• 52. When electrons in an atom change levels, the
atom emits.

A specific spectrum of color based on the energy
level of the electron.
53
• 53. The photoelectric/ photoemissive effect
means..

many metals emit electrons when light shines upon
them. Electrons emitted in this manner may be
called photoelectrons.
54
• 54. When the intensity of light increases, what
happens to the number of photoelectrons that are
emitted?

The number increases.
55
• 55. How much energy is used by a 500 watt dryer
that runs for 2½ hours?

Energy is measured in Kilowatt hours (KwH). 500
watts times 2.5 hours 1250 watt hrs. Divided
by 1000 to change to Kwhr 1.25 Kwhr
56
• 56. Inside the atom, what force holds the protons
and neutrons together?

The strong force.
57
• 57. Inside the atom, what force holds the
electrons to the atom?

The weak force.
58
• 58. Inside the atom, which is stronger, the
strong force or the gravity between the
particles?

At the distances inside the atom, the strong
force is stronger.