tacomafc
Senior Member
- Location
- Long Island New York
If a lamp is rated 500 watts at 115 volts. What is the watts at 120 volts?
If a lamp is rated 500 watts at 115 volts. What is the watts at 120 volts?
So you don't divide the watts by 115 and then multiply the result by 120?
Then the answer to #2 is wrong.Ok here is the full story. It was actually a 3 part question on a liscense exam that I took last night.
1) What is the resistance of a 500 watt quartz lamp rated at 115 volts.
answer : R= E x E / P 115 x 115 / 500w =26.45
2) What is the amps at 120 volts?
answer: I = 500/120 = 4.16
3) what is the wattage at 120 volts?
answer: P = E x E / P 120 x 120 / 26.45 = 544 watts
thank you for your time.
2) guess I should have I = E / R 120 / 26.45 = 4.53
if this is wrong PLEASE let me know how its done. thanks
Ok here is the full story. It was actually a 3 part question on a liscense exam that I took last night.
1) What is the resistance of a 500 watt quartz lamp rated at 115 volts.
answer : R= E x E / P 115 x 115 / 500w =26.45
2) What is the amps at 120 volts?
answer: I = 500/120 = 4.16
3) what is the wattage at 120 volts?
answer: P = E x E / P 120 x 120 / 26.45 = 544 watts
thank you for your time.
Following are measured resistance values of a 100 W 120 V bulb:
60.8 V --- 106.1 ohms
100.4 V --- 133.3 ohms
110.2 V --- 139.1 ohms
114.5 V --- 141.7 ohms
120.2 V --- 144.8 ohms
Ok here is the full story. It was actually a 3 part question on a liscense exam that I took last night.
1) What is the resistance of a 500 watt quartz lamp rated at 115 volts.
answer : R= E x E / P 115 x 115 / 500w =26.45
2) What is the amps at 120 volts?
answer: I = 500/120 = 4.16
3) what is the wattage at 120 volts?
answer: P = E x E / P 120 x 120 / 26.45 = 544 watts
thank you for your time.