[Home]
[Lessons] [Review]
[Search] [Links]
This web site is designed and maintained by Science Joy Wagon and may
not be reproduced or redistributed without written permission from Science Joy Wagon.
Contact with comments.
|
Physics Review Question Unit: Electricity Year: 1991 Question#: 29 Question: An Electric iron draws a current of 5 amperes and has a resistance of 20ohms. The amount of energy used by the iron in 40 seconds is (1 ) 100 J (2 ) 500 J (3 ) 4,000 J (4 ) 20,000 J What is this question really asking? Explanation by: Matt G [ Return to question menu ] Answer 1 100 J INCORRECT W=I2Rt If you do the math, the answer will be a lot bigger than 100J. return to top Answer 2 500 J INCORRECT Try the formula: W=I2Rt return to top Answer 3 4,000 J INCORRECT Try using W=I2Rt. return to top Answer 4 20,000 J CORRECT W=I2Rt. W=50A^2*20ohms*40 W=20,000 J return to top What's this question really asking? How do you find the energy used by an electrical appliance when given the current, resistance and time? return to top |
|
This web site is designed and maintained by Science Joy Wagon and may
not be reproduced or redistributed without written permission from Science Joy Wagon. |