Part of The Student Room Group

  • 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

or


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

    cells - 1.25 ohms - Series circuit with one cell - 1.25 ohms My hypothesis was 100% correct when predicting the internal resistance. I knew it would be correct because I used the relevant equations of finding total resistance in parallel and series, considering the internal resistance as a resistor:

  2. 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.

  1. Investigating the Number of Turns on the Secondary coil of a Transformer.

    lines of flux cut it, therefore the more wires that are cut by the changing magnetic field, the greater the current as effectively more lines of flux are cut per unit time.

  2. 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.

  1. eletrical dc motors

    A transformer is a device that transfers electrical energy from one circuit to another through inductively coupled electrical conductors. A changing current in the first circuit (the primary circuit) creates a changing magnetic field. This induces a changing voltage in the second circuit (the secondary circuit)

  2. The electrolysis of copper from copper sulphate solution

    more accidents are to great in this situation and therefore I must carefully walk to the nearest tap to wash off the solution.

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

    From the formula, we can know that the magnitude of the kinetic friction is direct proportional to the normal reaction force as the coefficient of kinetic friction is constant. The factors that can affect the kinetic friction are same as that of the static friction.

  2. AC Generator

    Glue the pieces to the big block base wood (see diagram). 6. Get the two thing metal pieces (brushes) and bend the tips of one end for each brush. Glue each one down to the base under a slip ring each so that they just touch (see diagram).

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