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**Ohm's law and AC circuits/ Biots / Oscilliscope**

hey wasssup...

i'm doing a practice final and need some help ...

It's askin which is true

(1) Ohm's Law is true for all materials;

(2) Resistance may depend on temperature

(3) REsistance may depend on current

(4) Ohm's law is empircal

(a) 1 and 2

(b) only 1

(c) only 2 and 3 and 4

(d) none of the above

(1)Clearly Ohm's Law states that V = IR or in some other order

Now it doesn't have any material constant in there so would one be ruled out ?

(2) Resistance may depend on temperature : This is true but it's not stated in ohms law

(3) Resistance doesn't depend on current, but current and resistance is needed for ohm's law

(4) Ohm's law is empircal ... it's not an observation but a LAW....

so is my choice D?

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(2) The voltage that is delivered by the electric power companies to domestic consumers has a frequency of 60z and PtP amplitude is closest to :

(a) 330 Volts

(b) 100 Volts

(c) 50 Volts

(d) 1200 Volts

I think in the us the AC voltage is 120 volts... (JPN is 100 V.. i always get these two mized up) anyhow assuming it's 120 Volts and Hz = 60 then wouldn't t = 1/2 * f because it's PtP

So V(t) = Vptp * Sin (w * t) .... yea i did this and i didn't get a matchin number.. hahahaha... thanks ahead a times

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