Lec 23 | MIT 8.02 Electricity and Magnetism, Spring 2002

Review Exam 2

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[TheRealBanana]

@OKMUNWURX

When you are dealing with AC circuits half the time the circuit is at 0V, which is why its 1/2*I^2*R

[surfax100]

My guess is that using a variable resistor is less efficient than using a variable inductor because it involves heat loss. as the second law of thermodynamics indicates there is no perfect engine.

[OKMUNWURX]

Since when does a 100 volt 100 ohm light bulb, which draws 1 ampere, operate at 50 watts? See 44:nn - 47.nn time

[OKMUNWURX]

Since when does a 100 volt 100 ohm light bulb, which draws 1 ampere, operate at 50 watts? See 44:nn time

[OKMUNWURX]

Since when does a 100 volt 100 ohm light bulbwhich draws 1 ampere, operate at 50 watts?

[kotofu]

Great review. I love how he focuses on the concepts rather than on the math.

[mdinka]

@DrTruffaldino no the formula is correct as he uses the unit vector of r check wikipedia

[musicofthen]

@DrTruffaldino The form that he wrote it in is correct. Notice that in the numerator it is the unit vector r.

[musicofthen]

@DrTruffaldino No, Dr. Lewin is correct. Notice that it is r-hat and not r-arrow.

[musicofthen]

@DrTruffaldino No, Dr. Lewin is correct. Notice that it is r-hat and not r-arrow.