Determine the x coordinate of a point on the positive x axis where the electric field is zero; i.e., a test charge placed at this point would experience no force.

Circuit B

Explanation:

To know the correct answer to the question, we shall determine the reading of the ammeter i.e the current in each circuit. This can be obtained as follow:

For circuit A:

Resistance (R) = 5 ohms

Voltage (V) = 1.5 V

Current (I) =?

V = IR

1.5 = I × 5

Divide both side by 5

I = 1.5 / 5

I = 0.3 A

For circuit B:

We'll begin by calculating the total resistance in the circuit. This can be obtained as follow:

Resistance 1 (R₁) = 5 ohms

Resistance 2 (R₂) = 5 ohms

Total resistance (Rₜ) =?

Since they are in parallel connections, the total resistance can be obtained as illustrated below:

Rₜ = R₁ × R₂ / R₁ + R₂

Rₜ = 5 × 5 / 5 + 5

Rₜ = 25 / 10

Rₜ = 2.5 ohms

Finally, we shall determine the current in the circuit.

Resistance (R) = 2.5 ohms

Voltage (V) = 1.5 V

Current =?

V = IR

1.5 = I × 2.5

Divide both side by 2.5

I = 1.5 / 2.5

I = 0.6 A

For circuit C:

We'll begin by calculating the total resistance in the circuit. This can be obtained as follow:

Resistance 1 (R₁) = 5 ohms

Resistance 2 (R₂) = 5 ohms

Total resistance (Rₜ) =?

Since they are in series connections, the total resistance can be obtained as illustrated below:

Rₜ = R₁ + R₂

Rₜ = 5 + 5

Rₜ = 10 ohms

Finally, we shall determine the current in the circuit.

Resistance (R) = 10 ohms

Voltage (V) = 1.5 V

Current =?

V = IR

1.5 = I × 10

Divide both side by 10

I = 1.5 / 10

I = 0.15 A

SUMMARY:

Circuit >>>>>>> Current

A >>>>>>>>>>>> 0.3 A

B >>>>>>>>>>>> 0.6 A

C >>>>>>>>>>>> 0.15 A

from the above calculations, circuit B has the highest ammeter reading.