In the circuit diagram above, calculate the current in the 12 Ω resistor if the cell has an emf of 12V and an internal resistance of 1Ω
0.8A
1.0A
1.6A
2.4A
Explanation
Video Explanation
No video available
Post your Contribution
Discussions (23)
The selected answer is wrong:
E=I(R+r)
R=(12*6)/(12+6)
R=72/18=4
12=I(4+1)
I=12/5=2.4
V=IR
V=2.4*4=9.6
Current in 12 ohm resistor=9.6/12=0.8
REF: P. N. Okeke physics. Chapter 31
Look at that circuit and discover that there are maximum of three resistors of which two are in parallel and series to the internal resistance of the battery
I = E/(R+r)
But the R is the overall resistances in parallel
1/R = 1/6 + 1/12
R = 4ohms
OR
R =( 6×12)/(6+12)
R = 4ohms
Now back to the current
I = 12/(4+1)
I = 12/5
I = 2.4A
But this current flows through the series internal resistance and when it wants to flow through the arm of the parallel resistors it divide with the biggest resistor value having a small share of current while the smallest having a higher share
This is due to the fact that current must look for an easier part to flow
Using kirchooff 's current divider rule
Current through the 12ohms resistor
I = (6/(6+12) )× 2.4
I = 0.8A
I support Reg
being a parallel connection,they have different current so the answer should be 0.8 not 2.4
The answer is 0.8 yet myschool has not deemed it neccesary to correct the glaring error
You guys only calculated the total current in the circuit. You need to find the terminal p.d which is 9.6 and divide it by 12 to get 0.8.
my school the answer is 0.8 ooo
u Poeple should correct
u just found the the total current not the current across 12R
we are ask to find the current across the 12ohms resistor...
V=ir
12=i×12
i=12/12=1A
