I don't get these four. Please help!
1. A 120-volt power supply lights a lamp with a resistance of 600 ohms. What current flows through the circuit?
a. 0.2 A
b. 1.0 A
c. 5 A
d. 20 A
2. How many volts are required to produce a current of 20 amperes through a resistance of 100 ohms?
a. 5 V
b. 80 V
c. 120 V
d. 2,000 V
3. A fuse is designed to burn out when the current exceeds 10 amperes. If the voltage supply is 120 volts, what is the smallest resistance that can be used without burning out the fuse?
a. 6 ohms
b. 12 ohms
c. 110 ohms
d. 1,200 ohms
4. A 100-watt light bulb is used 100 hours in a given month. How much energy does it use in that month?
a. 10 kW x h
b. 100 kW x h
c. 1,000 kW x h
d. 10,000 kW x h
Thanks
2007-05-29 19:22:11 · 4 answers · asked by Anonymous in Science & Mathematics ➔ Physics
1-3 you need the equation V = IR, voltage equals current x resistance.
1. 120/600 = .2A so A
2. 20*100 = 2000V so D
3. 120/10 = 12 ohms so B
4. it's measured in kilowatt hours, so 0.1kW * 100 = 10kWxh so A
A
D
B
A
2007-05-29 19:30:52 · answer #1 · answered by anonymous_20003 3 · 0⤊ 0⤋
1 A
2 D
3 B
4 a
It's called 'Ohms Law' and I suggest you study it real long and hard. Find out what it is and how to use it or you're not going to survive whatever course it is you're taking âº
Doug
2007-05-30 02:31:17 · answer #2 · answered by doug_donaghue 7 · 0⤊ 0⤋
(1)- USE V=IR(OHMS LAW) ANS=(A)
(2)-USE V=IR ANS=(D)
(3)-USE V=IR ANS(D)
YOU WILL GET THE ANSWER.
2007-05-30 02:36:49 · answer #3 · answered by Anonymous · 0⤊ 1⤋
DO YOUR HOMEWORK!
2007-05-30 02:31:42 · answer #4 · answered by asimovll 3 · 0⤊ 0⤋