Physics Experiments and Concepts Summary

Contents

  • Section I: Experiments
    1. Determine unknown resistance by slide wire bridge
    2. Determine internal resistance of cell using potentiometer
    3. Determine EMF of a cell using potentiometer
    4. Determine EMF and internal resistance of cell by plotting V against I graph
    5. Determine Resistance of Voltmeter by Drawing Graph between R and 1/V
    6. Determine the relation between current and capacitance in AC circuits with capacitors

Experiment 1: Determine Unknown Resistance by Slide Wire Bridge

  • Apparatus: Meter bridge, galvanometer, resistances, jockey, rheostat, cell, and wires.
  • Theory: Meter bridge operates on Wheatstone's principle.
  • Formula: [ \frac{P}{Q} = \frac{X}{R} ] at balance point.
  • Mean Resistance: Compute from multiple readings.

Experiment 2: Determine Internal Resistance of Cell Using Potentiometer

  • Apparatus: Potentiometer, cell, ammeter, resistance box, rheostat.
  • Theory: The potential difference across the cell is measured when balanced against the potentiometer wire.
  • Formula: [ r = \frac{R \cdot (L1 - L2)}{L_2} ]

Experiment 3: Determine EMF of a Cell Using Potentiometer

  • Apparatus: Potentiometer, cell, rheostat, voltmeter.
  • Theory: Relationship between lengths of wire balanced against EMF.
  • Formula: [ E = k \cdot L ]

Experiment 4: Determine EMF and Internal Resistance by Plotting V Against I Graph

  • Apparatus: Ammeter, voltmeter, internal resistance box.
  • Theory: Graphical method to find EMF and internal resistance from V-I characteristics.
  • Graph Interpretation: Slope gives internal resistance.
  • Formula: [ E = V + Ir ]

Experiment 5: Determine Resistance of Voltmeter by Drawing Graph between R and 1/V

  • Apparatus: Voltmeter, battery, high resistance box.
  • Theory: Relationship between voltage across the voltmeter and resistance.
  • Formula: [ R_v = \frac{E}{V} - R ]

Experiment 6: Relation Between Current and Capacitance in AC Circuits

  • Apparatus: AC ammeter, voltmeter, capacitors, transformer.
  • Theory: Current leads voltage in AC circuits, deriving capacitance relations using C.
  • Graph: Current (I) vs Capacitance (C) shows linear relationship.

Section II: Solutions

  1. Solving Queries for Each Experiment, including circuit configurations, expected measurements, and critical questions about resistivity, voltage, internal resistance, as well as fundamental properties of capacitors and thermistors.
  2. Discussion on Photovoltaic and Thermistors: Photocell operation, photoelectric effect, thermistor behaviour under varying conditions.

General Notes on Essential Concepts

  • Ohm's Law: [ V = IR ]
  • Potential Difference (P.D.): Measured in volts, describing energy per unit charge.
  • Capacitance and Charge Storage: Direct relationship with current in AC circuits; characterized by steady-state conditions for accurate assessments.