Electric Current Booklet!

Answers for pages 44, 45, 46

p. 44

1a. volts
b. voltage
c. current

2a. 1
b. 15
c. 1
d. narrow pipe,thin wire

p. 45

1. 1.5x10^-3 A
2. 4 A
3. 1.2 A
4. 4A
5. 1.5 x 10^-2 A -> 3.0 x 10^-2 A
6. 1000 Ω
7. 10 Ω
8. 100 V
9. Yes the resistance change, case 1: 240 Ω case2: 50 Ω

p. 46

1. R=pL/A, A=pL/R, A= (1.72 x 10^-8 Ω·m )(20 m) / (.10 Ω)
A= 3.44 x 10^-6 m^2

d= sqr(4A/π) d= 2.09 x10^-3 m

2. A= (0.25 x 10^-3 m)(1 x 10^-3m) A=2.5 x 10^-7 m^2

L= RA/p L=(1.5Ω)(2.7 x 10^-7 m^2) / (100 x 10^-8 Ω·m )
L= 0.38m

3. p=RA/L p= (0.04 Ω)(2 x 10^-6 m^2) / 5m
p= 1.6 x 10 ^-8 Ω·m

4. L= RA/p L= (3 Ω)(1.5 x10 ^-6 m^2) / (100 x 10^-8 Ω·m )
L= 4.5m

5. A = pL/R A= ( 55 x 10^-8 Ω·m )(.2m) / .10 Ω
A= 1.1 x 10^-7 m^2

d= sqr(4A/π) d = sqr((4 x 1.1 x 10^-7 m^2) / π)
d= 3.74 x 10 ^-4 m

NOTE:
Nichrome resistivity is 100 x 10^-8 Ω·m
Tungsten resistivity is 55 x 10^-8 Ω·m


We also need to answer the 2 questions on the bottom of page 14 on separate sheet of paper

The next one to scribe is ctc