After getting everything wrong last time, Bob now asks for help when he\'s confu

Question

After getting everything wrong last time, Bob now asks for help when he's confused. Help him become less confused by answering his questions below. a) "I don't understand how light bulbs can come on instantly after you flick the switch. Doesn't it take at least a second or two for the electrons to travel from the wall all the way up the wire into the light bulb?" b) "I have two equations for electrical power: P = l^2R and P = V^2/R. The first one makes it look like increasing resistance R will increase my electrical power, but the second one says that increasing R makes power decrease. One of them must be right: if I replace a 10 ohm resistor in a circuit with 20 ohm resistor, will the power going to that resistor increase or decrease? Bob's confusion continued c)"I need a 6 mu F capacitor for a cool circuit I'm making. Can't I just connect a 2 mu F and 4 mu F in series? d)"Speaking of capacitors, since C = Q/V, that means if Q = 0, then C = 0 too, right? e)"Why are there at least two prongs on every electrical plug? If power is traveling in one direction (from the wall to the appliance), why can't there be just one wire carrying it? And don't just say because circuits need to be closed' -after all, current can flow through a capacitor, and that's an open circuit. f) "I have a great idea that should make me filthy rich. I'm going to build a generator with a huge number of loops and an enormous magnetic field, but also with very low friction materials. That way, the opposing force against the spinning loops will be negligible. Therefore due to inertia, the loops will spin forever, with only very minimal input power to overcome the tiny amount of friction. In other words, I have found a loophole in conservation of energy: more electric power will be output than the mechanical power that was input. Who can stop me?!"

Explanation / Answer

a.) when we switch on the circuit the electron only vibrate on its own position it does not move throught out wire each electron just pushes another elctron so it will take no time to glow the bulb.

b.)P=I^2/R and P=V^2/R

V = IR

here R is constant

P = (IR)^2/R = I^2/R

if we change the resistance then current will change

and hence power will also change

c.)no, we cannot connect in series to make 6uF capicitor by 4uF and 2uF

we need to connect capacitor in parallel

C = C1+C2 = 6uF

d.)Q= CV

where C is constant

if Q=0 then V become zero and C remain constant

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.