Ohm's Law and Series Circuits HW

From Handout:

2. 1200 Ohms
3. 10 V, 20 Ohms
4.
b)60 Ohms,
c)0.2 A
d) 15 Ohm - 3 V, 21 Ohm - 4.2 V, 24 Ohm - 4.8 V
e) .6 W, .84 W, .96 W
f) .6W + .84 W _ ,96 W = 2.4 W OR (.2 A * 12 V) = 2.4 W
g) thickest filament - smallest resistance, since it has a larger cross sectional area. This must be the 15 Ohm resistor.
h) The brightest bulb uses the most power - this is the 24 Ohm bulb.

From book:
p. 551:
5. 35.5 Ohms
7. 2.1 x 10²¹ electrons
9. 24 Ohms, 360 W
26. Since P = V²/R, and V is the same for both, the resistance must be less for the higher power. Assuming a wall voltage of 120 V, the resistances are 24 Ohms and 12 Ohms for the 600 W and 1200 W settings.
31.
a) 8.57 Ohms, 1.05 W
b) 4 times the power. The bulb would probably not last for long!

p. 581
10. 27 Ohms