# GCSE Physics Question

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#1
So I was convinced I had got this question right on my mocks, but my teacher said I did it wrong and won't tell me how to redo it. I got 7A as the answer??

The battery powers 4 motors in the drone. Each motor has a resistance of 1.6 Ohms when the power input is 19.6W. The 4 motors are connected in parallel with the battery. Calculate the current in the battery.
0
2 years ago
#2
(Original post by mamasaywhatnow)
So I was convinced I had got this question right on my mocks, but my teacher said I did it wrong and won't tell me how to redo it. I got 7A as the answer??

The battery powers 4 motors in the drone. Each motor has a resistance of 1.6 Ohms when the power input is 19.6W. The 4 motors are connected in parallel with the battery. Calculate the current in the battery.
I got 3.5 amps
0
2 years ago
#3
Not sure if i'm right but i got 1.75 amps

edit: above answer is correct i think, i worked it out as if it was series rather than parallel
0
2 years ago
#4
(Original post by mamasaywhatnow)
So I was convinced I had got this question right on my mocks, but my teacher said I did it wrong and won't tell me how to redo it. I got 7A as the answer??

The battery powers 4 motors in the drone. Each motor has a resistance of 1.6 Ohms when the power input is 19.6W. The 4 motors are connected in parallel with the battery. Calculate the current in the battery.
Answer is 1.75 amps I meant
0
2 years ago
#5
(Original post by ray44)
Not sure if i'm right but i got 1.75 amps

edit: above answer is correct i think, i worked it out as if it was series rather than parallel
It’s either 3.5 or 1.75 I’m not surw
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2 years ago
#6
It will be 1.75 because total current is 3.5A. In parallel current 1 + current 2=current total
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#7
(Original post by Mitchchambo)
It will be 1.75 because total current is 3.5A. In parallel current 1 + current 2=current total
How did you work that out? Because I tried to find the total resistance first which is 1/Rt = 1/R1 +1/R2 +1/R3 +1/R4
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2 years ago
#8
(Original post by mamasaywhatnow)
How did you work that out? Because I tried to find the total resistance first which is 1/Rt = 1/R1 +1/R2 +1/R3 +1/R4
Use the formulae v=isquaredr
Rearrange to get I
1
2 years ago
#9
(Original post by Skkkk)
Use the formulae v=isquaredr
Rearrange to get i
Isnt the parallel equation p=v2÷r for dissipation in parallel
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2 years ago
#10
P = I^R
I = square root of P/R
The current of each resistor is the square root of 19.6/1.6
Which is 3.5
The current in a circuit splits off and the total current going in is the total going out so the total current is 3.5×4 which is 14
I think this is right, I got your answer at first but I think the reason it is wrong is because if you work out the total resistance then you're assuming that the power is not the same everywhere in the circuit when I think it is if you get me. I'm an A level physics student so this should be easy to me lol. 90% sure this is wrong
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