Question

4) You have a 10 ohm resistor connected in series with an ammeter. The voltage applied to the whole circuit is 1.2 volts. At the same time you have a voltmeter connected across the 10 ohm resistor and voltmeter reads 0.9 volts. The circuit draws a total of 0.5 amps. Can you determine resistance of the ammeter

Answer 1

Answer:

Explanation:

Given that,

Resistor R = 10 ohms

The resistor is connected in series with an ammeter to calculator the current that flows in the circuit.

Voltage applied V = 1.2 V

There is also a voltmeter across the 10 ohms resistor to know the potential difference across the resistor.

If the voltmeter reads 0.9V.

This shows that the voltage across the resistor is 0.9V

Vr = 0.9V, which is the terminal voltage

The ammeter reads a current of 0.5amps

This show that, the current that flow in the circuit is 0.5A

Ir = 0.5A

Internal resistance r of the ammeter?

Using KVL

V = I(r+R)

V = Ir + IR

Where IR is the terminal voltage Vr

V = Ir + Vr

Ir = V—Vr

Ir = 1.2—0.9

0.5r = 0.3

r = 0.3/0.5

r = 0.6 ohms

Answer 2

Answer:

0.6 Ω

Explanation:

As shown in the diagram below,

Since the resistance and the ammeter are connected in series,

(i) The same amount of current flows through them.

(ii) The sum of their individual individual voltage is equal to the total voltage of the circuit.

Applying ohm's law,

V = IR................ Equation 1

Where V = Voltage across the ammeter, I = current flowing through the ammeter, R = resistance of the ammeter.

make R the subject of the equation

R = V/I............... Equation 2

Given: V = 1.2-0.9 = 0.3 V, I = 0.5 A.

Substitute into equation 2

R = 0.3/0.5

R = 0.6 Ω