Question

a) Draw the diagram of a circuit consisting of a battery of three cells of 2V each, a 5 ohm
resistor, an 8 ohm resistor and a 12 ohm resistor, and a plug key, all connected in series.
(b) Redraw the above circuit putting an ammeter to measure the current through the
resistors and a voltmeter to measure the potential difference across the 12 ohm resistor.
What would be the readings in the ammeter and the voltmeter?

Answer 1

Answer:

(A) The circuit diagram is given in attachment.

(B) The circuit diagram is given in attachment.

Given:-

• Potential difference = 6 V
• Net resistance = 25 ohm

• Finding the Current (Ammeter reading) –

V = I * R

6 V = I * 25

I = 6/25

Ammeter reading = current = 0.24 A

• Finding the voltmeter reading or the potential difference across 12 ohm resistor –

V = I * R

V = 0.24 * 12

Potential differennce = Voltage = 2.88 V

________________

• An Ammeter is always connected in series.
• A Voltmeter is always connected in parallel to the resistor.
• An Ammeter is used to find out the current.
• A Voltmeter is used to find out the potential difference across the resistor.

Answer 2

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QUESTION -

( a ) Draw the diagram of a circuit consisting of a battery of three cells of 2V each, a 5 ohm resistor, an 8 ohm resistor and a 12 ohm resistor, and a plug key, all connected in series.

( b ) Redraw the above circuit putting an ammeter to measure the current through the resistors and a voltmeter to measure the potential difference across the 12 ohm resistor.

( c ) What would be the readings in the ammeter and the voltmeter?

SOLUTION -

See the above attachments.

We have the following information ...

The net resistance is equal to the sum of the given resistances as they are in series.

R_{Equivalent } : 5 Ohm + 8 Ohm + 12 Ohm = 25 OhM.

Net Voltage = 2V × 3 = 6 Volts.

Now,

According to Ohm ' s Law,

V = I R

V is the voltage in the circuit.

I is the net current in the circuit.

R is the net resistance.

Now,

Substuting the required values -

6 = 25 I

=> I = { 6 / 25 } Amperes = 0.24 Amperes.

So the required reading of the ammeter is 0.24 Amperes.

[ B ] Voltage Reading Across 12 Ohm Resistor :

We are using the same law here ,

Potential Difference , V = I ×R

=> V = 0.24 × 12 V = 2.88 Volts.

ANSWER :

In the circuit above,

The readings of the ammeter and the voltmeter are -

• 0.24 Amperes

• 2.88 Volts

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