In a given circuit, the cell P has an emf 1.5V and an unknown internal resistance while cell Q has an emf 2.0V and an internal resistance of 1 ohm if the ammeter reads 50m A, Then r is equal to

harmhee06

3 years ago

Jamb 1979: in the circus below the cell P has an e.m.f 1.5v and an unknown internal resistance of r while the cell Q has an e.m.f of 2.0v and an internal resistance of 1ohms if d ammeter reads 50mA, then r equals?

Emmanuel24458

2 years ago

Here is a simple way

E-v=I(R+r+r)
1.5-2=50x10^-3(7+1+r)
0.5v=0.05amp(8+r)
Expand
0.05amp(8 + r)
0.5v=0.4+0.05r
Find r
0.5-0.4=0.1
0.1/0.05=2

ayorinde01

5 years ago

Or use this method👇👇👇

BIG S

1 year ago

Omo physics🥴🥱

OsagieN

2 years ago

𝐃

LorrLouis

1 year ago

always have an explanation for every question

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Giddywise

6 years ago

please my school i need contribution for dat very question

Dentine

2 years ago

Thanks for the explanations.....But I think the best way of knowing this thing better ...is by checking the different contributions made by others and finally meditating specifically on that of Shile method...Thanks

Ikoifrancisusang

6 years ago

myschool I don't understand this question, explanation is needed pls

Fe1fe1fe1fe1

3 years ago

Can someone please explain more in details

Som15432

1 year ago

The unknown internal resistance (r) of cell P is 2.0 ohms. This corresponds to option D in the provided image.
To calculate the internal resistance, the following steps can be used:
1. Calculate the total resistance in the circuit:
Total resistance (R) = External resistance + internal resistance of cell Q + internal resistance of cell P
R = 7 ohms + 1 ohm + r = 8 + r
2. Apply Ohm's Law:
Total voltage (V) = Current (I) * Total resistance (R)
The total voltage in the circuit is the difference between the EMFs of the two cells since they are connected in opposition: V = 2.0V - 1.5V = 0.5V
Convert the current from milliamperes to amperes: I = 50 mA = 0.05 A
0.5V = 0.05A * (8 + r)
3. Solve for r:
0.5 = 0.4 + 0.05r
0.1 = 0.05r
r = 0.1 / 0.05
r = 2.0 ohms