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Equivalent Resistance in Series and Parallel

Physics Hard

Aim

To determine the equivalent resistance of two resistors when connected in series and in parallel.

Materials Required

Two resistors
Ammeter
Voltmeter
Battery
Switch
Connecting wires

Procedure

  1. Connect the battery, ammeter, switch, and two resistors (R1 and R2) in series.
  2. Connect a voltmeter in parallel across the two resistors.
  3. Close the switch and record the ammeter and voltmeter readings.
  4. Now, connect the two resistors in parallel.
  5. Connect the ammeter in series with the battery and the voltmeter in parallel across the parallel combination.
  6. Record the current and voltage. Compare observed values with calculated values.

Precautions

  • Ensure all connections are tight.
  • Use an ammeter and voltmeter of appropriate range.
  • Do not pass current through the circuit for a long time to prevent heating of resistors.

Controls

Live Readings

Equivalent Resistance: 0.00 Ω
Total Current (I): 0.00 A
Voltage across R1 (V1): 0.00 V
Voltage across R2 (V2): 0.00 V

Observation Table

S.No. Mode R1 (Ω) R2 (Ω) Voltage (V) Equivalent R (Ω) Total Current (A)

1. In series combination, current through each resistor is:

Current remains same across all components in a series circuit.

2. Equivalent resistance in parallel is:

In parallel, the equivalent resistance is always less than the smallest individual resistance.

3. If R1=2Ω, R2=3Ω in series, equivalent resistance =

In series, equivalent resistance is the sum: 2Ω + 3Ω = 5Ω.

4. In parallel, voltage across each resistor is:

Voltage is same across all parallel branches in a circuit.

5. Which combination gives less overall resistance?

Parallel combination always results in a lower equivalent resistance.

Experiment Report

Title:

Equivalent Resistance in Series and Parallel

Aim:

To determine the equivalent resistance of two resistors when connected in series and in parallel.

Recorded Observations:

Mode V (V) R1 (Ω) R2 (Ω) Req (Ω) I (A)
No observations recorded yet.

Result:

The equivalent resistance in series is R1 + R2 (sum). The equivalent resistance in parallel is (R1 × R2) / (R1 + R2) (less than smallest).