Download presentation

Presentation is loading. Please wait.

Published byGabriella Thomson Modified over 2 years ago

1

2
Here we have an apple that is at a height h above the Earths surface.

3
The apple has a potential energy equal to

4
Anywhere along the dotted line the apple has the same height, therefore the same potential energy.

5

6

7
This line that has the same potential is called an line.

8
This line that has the same potential is called an line.

9
For any object there is an infinite number of lines.

10
Here we show some of the different lines.

11
If we moved the apple along one of these lines

12
there would be no change in potential energy therefore no work would be done.

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31
Once again, there was NO WORK done in moving the apple along the from point A to point B.

32
We also know that if we raise an apple above the Earth and let it go, it will fall.

33

34

35

36

37

38
The direction that the apple accelerates tells us the direction of the gravitational force.

39
The direction of the gravitational force and the pattern of equilpotential lines give us a view of the. By Richard J. Terwilliger

40
around the Earth.

41
means that there will be a gravitational force on an object if it is placed in the field.

42
Could this model also work with

43
And how would we deal with two different net charges?

44
Lets start with an object that has a NET NEGATIVE charge.

45

46

47

48

49

50

51

52

53
Placing a test charge in the vicinity of this net negative charge and noticing if it experiences a force will tell us if there is an Electric Field around the charge.

54
It will also tell us the direction of the Electric Field.

55
The test charge is always defined as

56
Therefore the test charge has a force acting on it the net negative charge.

57
This is the direction of the

58
Moving the test charge around the net negative

59
and plotting the direction of the force will show us the field surrounding the charge.

60
This positive test charge if free to move will fall towards the net negative charge.

61

62
The positive test charge has no potential energy at this point.

63
To pull the positive test charge away from the negative we must do work on the positive test charge.

64
This work is equal to the potential energy at that point.

65
So similar to the equipotentials surrounding the Earth,

66
we have equal potentials surrounding the net negative charge.

67
If the charge moves along the equipotential there is no work done.

68

69

70

71

72

73

74

75

76

77

78

79

80

81

82

83

84

85

86

87
By Richard J. Terwilliger

88
If the charge moves along the equipotential there is no work done. By Richard J. Terwilliger

89
If the charge moves along the equipotential there is no work done.

90

91

92

93

94

95

96
By Richard J. Terwilliger

97
If the charge moves along the equipotential there is no work done.

98

99

100
We now know the direction of the force and the pattern of equipotentials around the net negative charge.

101
Notice the lines of force are at right angles to the equipotential lines. 90 o

102

103
We can now predict the electric lines of force and the equipotential lines around a charge.

104
A positive test charge placed near the net positive charge will experience a force outward.

105
Therefore the electric field surrounding the net positive radiates out away from the positive.

106
And the equipotential lines must cross these force lines at right angles forming concentric circles.

107
Notice the force lines never cross each other and the equipotential lines never cross.

108
So we now know what the fields look like around either a positive or negative charge

109

110
What would the electric field lines and the equipotential lines look like around two charges?

111
One negative and one positive.

112
First we place our positive test charge in the field and determine the direction of the force on the test charge.

113
The test charge is repelled away from positive and attracted toward the negative.

114
Now move the test charge to a new position and determine the direction of the force.

115
Keep moving the test charge and determine the direction of the force at each new position.

116

117
If we place the test charge at the position shown,

118
The test charge will experience a large force pushing it away from the positive charge and

119
A very small force pulling it towards the negative charge.

120
The electric field, at this point, would be the resultant of these two forces.

121
Move the test charge and again find the resultant.

122
Here the test charge is further away from the positive charge so the force is smaller.

123
Move the test charge and again find the resultant force.

124
Keep repeating until you have the pattern for the electric field line, the line of force.

125
Once more.

126
Connecting all of these arrows gives us the electric field line.

127
From here we can finish the pattern.

128
Now draw in the Remember, they never cross each other and must cross the force lines at right angles.

129

130

131

132

133

134

135

136

137

138

139

140

141

142

143

144

145

146

147

148

149
What does the Electric Force lines and Equipotential lines look like between parallel plate charges?

150

151
Lets check it out!

152
First well start with two parallel plates.

153
Next well charge one plate net negative and the other plate net positive.

154
To determine the direction of the electric field well place the test charge between the plates.

155
Remember the test charge?

156
Is the test charge positive or negative? CLICK on YOUR ANSWER

157
Hello? McFly!

158
The electric field direction is determined using a net test charge

159

160
A positive charge placed between the two parallel plates

161
will be forced away from the positive plate and towards the negative plate.

162

163

164

165

166

167

168

169

170

171

172

173

174

175

176

177

178

179

180

181

182

183

184

185

186

187

188

189

190

191

192

193

194

195

196

197

198

199

200

201

202

203

204

205

206
Therefore the electric field direction between two parallel charged plates is away from the positive plate and towards the negative plate.

207
And the equipotential lines are perpendicular to the force lines.

208

Similar presentations

© 2016 SlidePlayer.com Inc.

All rights reserved.

Ads by Google