ALL PHYSICS DOUBTS - POST HERE !!

[guMnam]

It depends if the circuit is series or parallel.

for example..if it is parallel??

[Ivo]

for example..if it is parallel??

Then if V=IR, so re-arrange I=V/R, so V is constant, so if you increase the resistance, then you decrease the current.

[diva_sparkles]

Firstly, its P=I²R

it can also be H=I^2R
H is heat in this case

[Malak]

How do u calculate the answer...
thx

[8T]

Could someone spare his time & explain total internal reflection for me?

[Snake]

Thanks a lot!!    and another thing wht is the relationship between the resistance of a wire and its length and diameter?

Length - If length increases (lets say by x2) then the resistance increases by x2 because it takes 2 times the amount of time for the current to travel! (Increase in length=Increase in Resistance)
Crossectional area (diameter) - If the area decreases then resistance increases, however if area increases then resistance decreases ( Decrease in area=Increase in Resistance)

Hope I helped elaborate a bit more

Guys I have a doubt, what is a Capacitor? and its properties?

[guMnam]

Then if V=IR, so re-arrange I=V/R, so V is constant, so if you increase the resistance, then you decrease the current.

so mainly it depends on the equatin..there is no rule??...

[Ivo]

Could someone spare his time & explain total internal reflection for me?

TIR happens when angle of incidence (IN OPTICALLY DENSER material) is more than critical angle.

[jellybeans]

How do u calculate the answer...
thx

5 hours is 1/4 of 20 hours.
you need to find what is WAS .. so you repeat (0.48*2) for 4 times. this is cuz it was halved for 4 times to reach 0.48, so to find what is was before, you times 2 by 4 times.. eek, geddit? >_<
0.48*2*2*2*2 = 7.68g

[Ghost Of Highbury]

How do u calculate the answer...
thx

0.48*2*2*2*2 = 7.68

7.68 after 5 hours = 3.84

after 10 hours = 1.92

after 15 hours = 0.96

after 20 hours = 0.48

[Ivo]

so mainly it depends on the equatin..there is no rule??...

Yep, kind of.

[holtadit]

How do u calculate the answer...
thx

Okay.....

There a FOUR half lives involved in this each FIVE hours long = 20 hours altogether.

Okay, if you knew the ORIGINAL mass (lets say Xg) at the START what would you have done ?  X/2= something which you would have divided by 2 and so on.

For this you need to wrk backwards.

0.48*2= 0.96

0.96*2= 1.92

1.92*2= 3.84

3.84*2= 7.68 g

[Ghost Of Highbury]

it can also be H=I^2R
H is heat in this case

High voltage direct current (HVDC) is used to transmit large amounts of power over long distances

P = V*I

P is constant, thus, a large value of voltage is used to reduce the current.

H = I^2r

I reduces, H reduces. Thus the heat loss is reduced.

[Raywin]

Length - If length increases (lets say by x2) then the resistance increases by x2 because it takes 2 times the amount of time for the current to travel! (Increase in length=Increase in Resistance)
Crossectional area (diameter) - If the area decreases then resistance increases, however if area increases then resistance decreases ( Decrease in area=Increase in Resistance)

Hope I helped elaborate a bit more

Guys I have a doubt, what is a Capacitor? and its properties?

THANKS A LOT! YES U DID..  AND A capacitor is something tht looks like this || on a circuit. Wht it does is when connected to a circuit with a switch closed, it charges. Charge is stored in it. When the switch is open, it lets these charges out AFTER a delay and it discharges.

[holtadit]

This is like a private study period.

LMAO !