• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

Aim: To investigate the factors affecting the e.m.f. induced in a coil due to a varying magnetic field in a neighboring coil.

Extracts from this document...

Introduction

Physics Formal Lab Report

Name: Yip Ka Man

Class: 6B

Class number: 31

Date: 16th April, 2008

Experiment number: C17

Aim:

To investigate the factors affecting the e.m.f. induced in a coil due to a varying magnetic field in a neighboring coil.

Apparatus:

1 CRO (dual trace)                                                      

1 Signal generator                                                      

1 Search coil (axial type)                                                

2 Square solenoids (different sizes)                                        

1 d.c. power supply                                                      

1 Light-beam galvanometer

1 a.c. ammeter

1d.c. ammeter

1 Rheostat

2 PVC-covered copper wire 26 s.w.g. (2 m long)

1 Magnetic field board

1 Stop watch

Connecting leads

Theory:

The electromagnetic induction is a phenomenon that a varying magnetic flux can induce an electromotive force (e.m.f.) in a coil. The induced e.m.f. depending on several factors can be described by the Faraday’s Law of Electromagnetic Induction:

Induced e.m.f. (ε) = -dΦ/dt

Where Φ is the magnetic flux enclosed by a one-turn-coil. Note that the negative sign denotes that the induced e.m.f. and induced current oppose the original change of magnetic flux.

If the magnetic flux linked with a coil of area A, having N turns and at right angles to the magnetic field of flux density B, the total magnetic flux (Φ) is NBA. Hence,

Induced e.m.f. (ε) = -NAdB/dt

Procedures:

A. Rate of change of magnetic flux

...read more.

Middle

  1. A graph of the induced e.m.f. (ε) against the number of turns (N) was plotted.

B. Number of turns of coil

  1. Steps 3 to 4 were repeated with the other values of numbers of turns of the copper coil around the solenoid. The results were tabulated.

No. of turns(N)

5

7

9

11

13

15

Induced e.m.f.(ε)/mV

0.04

0.05

0.06

0.07

0.08

0.09

  1. A graph of the induced e.m.f. against the number of turns was plotted.

C. Cross-sectional area of coil

  1. Two square solenoids of different cross-sectional areas were connected in series to the signal generator. The solenoids both had the same number of turns per unit length but one had a larger cross-sectional area than the other.
  2. 10 turns of the copper wire were wired tightly around the middle of each solenoid. One copper wire was connected to channel 1 of a dual trace CRO and the other to channel 2. The solenoids were kept well apart from each other.
  3. The signal generator was turned on and set to 1 kHz. The CRO setting was adjusted to display both whole traces on its screen.
  4. The time base of the CRO was switched off. The length of the vertical trace shown on the CRO was recorded, which represented the induced peak-to-peak e.m.f. in the copper coil for each solenoid.

Solenoid

Large

Small

Induced e.m.f.(ε)/mV

130

80

...read more.

Conclusion

From the results in steps 23 and 25 in Part E, it can be concluded that the induced e.m.f. is directly proportional to the rate of change of magnetic flux, i.e. a steady induced e.m.f. will result in a steady rate of change of magnetic flux.The solenoids are placed perpendicular to each other because this ensures that the magnetic field produced in each of the solenoids is not affected by that in the neighboring solenoids.Sources of error:

-There is reaction time of an individual.

-A stopwatch which is fast.

-The surrounding magnetic field of the neighboring solenoids may affect the experimental result.

-The setting and calibration of the CRO is wrong.

Suggested improvements:

-Repeat the experiment several times and take the average data for calculation.

-The time measured by a stopwatch is checked using another watch.

-Place the neighboring solenoids perpendicular to each other.

-Reset the setting and calibration of the CRO.

Conclusion:

From the experiment, it is observed that the factors affecting the e.m.f. induced in a coil due to a varying magnetic field in a neighboring coil are the rate of change of magnetic flux, the number of turns of coil and the cross-sectional area of coil.

...read more.

This student written piece of work is one of many that can be found in our AS and A Level Electrical & Thermal Physics section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related AS and A Level Electrical & Thermal Physics essays

  1. Objective: To use a search coil and a CRO to investigate the magnetic ...

    is induced across the ends of the coil. The induced e.m.f. (?) is directly proportional to the rate of magnetic field, i.e. ? = -NA dB/dt .When the search coil is connected to a CRO, the corresponding induced e.m.f. and hence magnetic field magnitude can be determined. Precautions for magnetic field around straight wire 1.

  2. Investigating the E.m.f and Internal Resistance of 2 cells on different circuit Structures.

    For a series circuit the total resistance is equivalent to the external resistance (R1) + internal resistance (r1) * 2. In a series circuit, I expected the internal resistance to be half of the series circuit with two cells -> 1* (r1).

  1. The potato - a source of EMF

    By having this bit of information it means I can calculate the maximum power of the potato. To see what the maximum power is I need to plot a graph of Power against Load Resistance, where the curve peaks will supposedly show the maximum power output possible for the potato cell.

  2. eletrical dc motors

    this is called mutual induction. By adding a load to the secondary circuit, one can make current flow in the transformer, thus transferring energy from one circuit to the other. In an ideal transformer, the induced voltage in the secondary winding is a fraction of the primary voltage and is

  1. To find the factors that affect the amount of E.M.F. being produced. The amount ...

    Coil of wire - produce the magnetic field, which magnetize the pieces of iron. 5. Two pieces of iron - to be magnetized into a magnet. 6. Circuit wire - for connecting up the circuit. 7. Oscilloscope - for measuring the amount of electro-motive-force being produced.

  2. The electrolysis of copper from copper sulphate solution

    This is how I will work out the Moles of electrons for each concentration. Concentration (Molar) Quantity of Electricity / C Moles of Electrons / C 1 63.6 0.0006625 0.8 37.2 0.0003875 0.6 27.6 0.0002875 0.4 16.8 0.000175 0.2 10.8 0.0001125 0 0 0 Analysis and Conclusion: In this experiment

  1. The aim of the experiment is to verify the maximum power theorem and investigate ...

    All wooden blocks were weighed by the beam balance and labeled with numbers. 2. The scale of the spring balance was set properly to zero. 3. The sand paper was placed on the table. 4. A wooden block was placed on the table.

  2. To investigate the effects of two different variables on a solar cell output.

    I will have enough results to establish a decent pattern between results. I will also then repeat the experiment in order to get more accurate results by making sure the results are correct and I can also obtain an average by adding the sets of results and dividing them by the number of different results taken.

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work