1- Consider Ohms’ law R = V/I , the ratio of V to I represents resistance in ohms.
2 - R= V/I = 100V/ 5A = 20Ω
3- (2) If more resistance is applied to a circuit voltage much is increased to keep the generator turning at the same speed. In Ohms’ law R= V/I if R in increased V must increase to maintain the same relationship.
4- (4) R= V/I 50 Ω = 5V/I I = .1 Amperes
5- (3) R= V/I 4 Ω = 12V/I I = 3 Amperes
6- (4) R= V/I R = 5V/.1 A = 50 Ω
7- (2) R= V/I 12Ω = 6V/ I I = .5 A
9- (a) First we must take notice that we have resistors in this circuit that are in parallel and series, therefore we must use both series and parallel rules to answer this problem. In the series segment of the circuit we should add 2Ω to 4Ω to determine the total resistance in that area. We then have two 6Ω resistors in parallel. In parallel we add 1/6Ω + 1/6Ω and get 12/36Ω which is equal to 1/Rtotal. Simply taking the inverse gives us a total resistance of 3Ω.
(b) To find the current of the circuit we simply use Ohm's law. R = V/I. In problem a we determined a resistance of 3Ω,so 3Ω= 12V/I. I = 4 amps.
10- All we have to do to solve this problem is use Ohm's law! R = V/I, 8Ω = 20V/I. I = 2.5 amps.
11) As the temperature of a metal increases its resistance also increases
12) Using Ohm's law, R = V/I , 3Ω = 12V/I, I = 4amps. The current through the resistor is 4 amps.
13) R = V/I, 40Ω = 10V/I, I = .25 amps
14) Simply add the four 7Ω resistors together. 7Ω+7Ω+7Ω+7Ω = 28Ω. The total resistance is 28Ω.