electrical currnt and current circuits for iit

8/9/2019 electrical currnt and current circuits for iit

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x

A q

v d

v d

t FIGURE 6.2 A section of a uniform

conductor of cross-sectional area A .The mobile charge carriers move withan average speed v d along the wire,and the displacement they experience


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v d

E

Figure 6.3

A schematic representation of thezigzag motion of a charge carrier in aconductor. The changes in direction


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F I G U R E 6 . 4 A uniform conductor of length and cross-sectional area A . A potential difference V b V a is maintai-ned across the conductor so that anelectric eld exists in the conductor,and this eld produces a current I that isproportional to the potential difference.

E:

b V a

I A

E

I

Slope = 1

I


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F I G U R E 6 . 6The colored bands on a resistorrepresent a code for determining resistance. The

rst two colors give the rst two digits in the

resistance value. The third color represents thepower of ten for the multiplier of the resistance

( S u p e r

S t o c

k )


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T

0

T

00

F I G U R E 6 . 7 Resistivity versustemp-erature for a normal metal,such as copper. The curve is linearover a wide range of temperatures,

and increases with increasingtempera-ture. As T approaches


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b

a

c

d

R

I

V +

Figure 6.9


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30 W

60 W

e f

c d

A

B


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+

Battery

R 1 R 2


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+

(a)

Battery

1 2

V

(c)

I

a c

(b)

I

R 1 R 2

I

a b c

I 1 = I 2 = I R eq = R 1 + R 2

V

Figure 6.13

(a) A series connection of two lightbulbs with resistances R 1 and R 2 . (b) The circuit diagram for the two-resistor circuit. Thecurrent in R 1 is the same as that in R 2 . (c) The resistors are replaced with a single resistor having an equivalent resistanceR eq R 1 R 2.


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(c)

I

V

b

(b)

I 1

R 1

R 2

V

a

I

I 2

+

(a)

R 1

R 2

Battery

V 1 = V 2 = V R eq R 1 R 21 1 1= +

Figure 6.14

(a) A parallel connection of twolightbulbs with resistances R 1 andR 2. (b) The circuit diagram forthe two-resistor circuit. Thepotential difference across R 1 isthe same as that across R 2. (c)The resistors are replaced with asingle resistor having anequivalent resistance given by Equation 6.29.

A B


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A B

C D

F I G U R E 6 . 1 5 (Thinking Physics6.4) What happens to the lightbulbs if one fails?


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14 0 V


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14.0 V e

b

4.0

10.0 V 6.0

f

I 2

c

I 3

I 1

2 0 d a I


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(a)

I 1

I 2

I 3

(b)

Flow inFlow out

Resistor


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+

Battery

Capacitor

Switch

(a)

(b)

S

t < 0

R

C

(c) t > 0

R

S

I q + q

Figure 6.22

(a) A capacitor in series with a

resistor, switch, and battery.(b) Circuit diagram represen-ting this system at time t < 0,before the switch is closed. (c)Circuit diagram at time . t > 0,after the switch has beenclosed.

q


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q

t

C

0.632C

(a)

I

=RC


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Switch Battery

C

Figure Q6.15

7 00


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9.00 4.00

10.0

7.00

b a

Figure P6.25

100


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2.00

18.0 V 3.00

4 00

1.00

a 100

100

b

Figure P6.27

R b

2R c d


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a

b

3R 4R

d

e

+ +

2

FigureP6.35

0.01

Livebattery

+ +

1.00 0.06Starter

Deadbattery

12 V 10 V

Figure P6.36

+ +


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A

R 1

(a)

R 2 A

R 1

(b)

R 2

F I G U R E 6 . 2 (Quick Quiz 6.6) What happens when the switch is opened?

(a)

A

R 1

R 2

(b)

A

R 1

R 2

F I G U R E 6 . 3 (Quick Quiz 6.7) What happens when the switch is closed?

(a)

+

+

++

+

++

(b) (c) (d)

F I G U R E 6 . 1 (Quick Quiz 6.1) Four groups of charges move through a region.

electrical currnt and current circuits for iit

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