physics question

[jstyt7]

Advertisement - Members don't see this ad

I attached a picture of a question from Achiever. I was wondering why the current should be still the same when you add a resistor shouldn't decrease ?? I remember that from Chad and I checked my notes that's what I have..
Please explain

 

[NECO_OD]

When you add a second resistor (R2) parallel to the original resistor (R1), the voltage across R1 would not change, so the current across R1 will still be the same (I=V/R). The total R has been reduced, so the total current will be increased.

 

[jstyt7]

When you add a second resistor (R2) parallel to the original resistor (R1), the voltage across both R1 would not change, so the current across R1 will still be the same (I=V/R). The total R has been reduced, so the total current will be increased.
View attachment 207765

If the voltage is 12V and 2 parallel resisters are 2 and 2, wouldn't the current across each of those be 1.5A ?
but if it 12 V and one resister of 2 .. the current will be 6A .. ??
so the one with two parallel resistor shows a decrease in current :/ does in it?? where am I going wrong ??

 

[NECO_OD]

If the voltage is 12V and 2 parallel resisters are 2 and 2, wouldn't the current across each of those be 1.5A ?
but if it 12 V and one resister of 2 .. the current will be 6A .. ??
so the one with two parallel resistor shows a decrease in current :/ does in it?? where am I going wrong ??

If R1=R2=2 omegas, since
1/Rtotal=1/R1+1/R2,
so Rtotal=1
Itotal=U/Rtotal=12/1=12A
And since the two resistances are parallel to each other, the total current should also be equal to I1+I2

I1=U/R1=12/2=6A
I2=U/R2=12/2=6A
I1+I2=12A which is consistent with the above calculation.