71.

(a) By symmetry, we see that i

1

is half the current that goes through the battery. The battery current

is found by dividing

E by the equivalent resistance of the circuit, which is easily found to be 6.0 Ω .

Thus,

i

1

=

1

2

i

bat

=

1

2

12 V

6.0 Ω

= 1.0 A

and is clearly downward (in the figure).

(b) We use Eq. 28-14: P = i

bat

E = 24 W.

Document Outline

• Main Menu
• Chapter 1 Measurement
• Chapter 2 Motion Along a Straight Line
• Chapter 3 Vectors
• Chapter 4 Motion in Two and Three Dimensions
• Chapter 5 Force and Motion I
• Chapter 6 Force and Motion II
• Chapter 7 Kinetic Energy and Work
• Chapter 8 Potential Energy and Conservation of Energy
• Chapter 9 Systems of Particles
• Chapter 10 Collisions
• Chapter 11 Rotation
• Chapter 12 Rolling, Torque, and Angular Momentum
• Chapter 13 Equilibrium and Elasticity
• Chapter 14 Gravitation
• Chapter 15 Fluids
• Chapter 16 Oscillations
• Chapter 17 Waves—I
• Chapter 18 Waves—II
• Chapter 19 Temperature, Heat, and the First Law of Thermodynamics
• Chapter 20 The Kinetic Theory of Gases
• Chapter 21 Entropy and the Second Law of Thermodynamics
• Chapter 22 Electric Charge
• Chapter 23 Electric Fields
• Chapter 24 Gauss’ Law
• Chapter 25 Electric Potential
• Chapter 26 Capacitance
• Chapter 27 Current and Resistance
• Chapter 28 Circuits
  • 28.1 - 28. 10
    • 28.1
    • 28.2
    • 28.3
    • 28.4
    • 28.5
    • 28.6
    • 28.7
    • 28.8
    • 28.9
    • 28.10
  • 28.11 - 28.20
    • 28.11
    • 28.12
    • 28.13
    • 28.14
    • 28.15
    • 28.16
    • 28.17
    • 28.18
    • 28.19
    • 28.20
  • 28.21 - 28.30
    • 28.21
    • 28.22
    • 28.23
    • 28.24
    • 28.25
    • 28.26
    • 28.27
    • 28.28
    • 28.29
    • 28.30
  • 28.31 - 28.40
    • 28.31
    • 28.32
    • 28.33
    • 28.34
    • 28.35
    • 28.36
    • 28.37
    • 28.38
    • 28.39
    • 28.40
  • 28.41 - 28.50
    • 28.41
    • 28.42
    • 28.43
    • 28.44
    • 28.45
    • 28.46
    • 28.47
    • 28.48
    • 28.49
    • 28.50
  • 28.51 - 28.60
    • 28.51
    • 28.52
    • 28.53
    • 28.54
    • 28.55
    • 28.56
    • 28.57
    • 28.58
    • 28.59
    • 28.60
  • 28.61 - 28.70
    • 28.61
    • 28.62
    • 28.63
    • 28.64
    • 28.65
    • 28.66
    • 28.67
    • 28.68
    • 28.69
    • 28.70
  • 28.71 - 28.80
    • 28.71
    • 28.72
    • 28.73
    • 28.74
    • 28.75
    • 28.76
    • 28.77
    • 28.78
    • 28.79
    • 28.80
  • 28.81 - 28.90
    • 28.81
    • 28.82
    • 28.83
    • 28.84
    • 28.85
    • 28.86
    • 28.87
    • 28.88
    • 28.89
    • 28.90
  • 28.91 - 28.96
    • 28.91
    • 28.92
    • 28.93
    • 28.94
    • 28.95
    • 28.96
• Chapter 29 Magnetic Fields
• Chapter 30 Magnetic Fields Due to Currents
• Chapter 31 Induction and Inductance
• Chapter 32 Magnetism of Matter: Maxwell’s Equation
• Chapter 33 Electromagnetic Oscillations and Alternating Current
• Chapter 34 Electromagnetic Waves
• Chapter 35 Images
• Chapter 36 Interference
• Chapter 37 Diffraction
• Chapter 38 Special Theory of Relativity
• Chapter 39 Photons and Matter Waves
• Chapter 40 More About Matter Waves
• Chapter 41 All About Atoms
• Chapter 42 Conduction of Electricity in Solids
• Chapter 43 Nuclear Physics
• Chapter 44 Energy from the Nucleus
• Chapter 45 Quarks, Leptons, and the Big Bang