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

# Find the relationship between the current through a resistor and the voltage across it.

Extracts from this document...

Introduction

Gunjan Jain

11D

May 8, 2007

MYP Physics Practical – Current and Voltage

Aim:

To find the relationship between the current through a resistor and the voltage across it.

Apparatus:

Power pack, Leads, Ammeter, Voltmeter, Resistor (Nichrome Wire)

Method:

Assemble the circuit shown above. Vary the emf of the power pack from 0 to 12 Volts. Measure the current on the ammeter and voltage on the voltmeter for each value of emf.

Data Collection:

## Thin Nichrome Wire

EMF

Current (Amperes)

Voltage (Volts)

0

0

0

2

0.15

1.75

3

0.27

2.5

4

0.38

3.25

5

0.5

4.25

6

0.6

5

8

0.85

7

10

1

9

12

1.2

10.5

## Medium Nichrome Wire

EMF

Current (Amperes)

Voltage (Volts)

0

0

0

2

0.38

1.6

3

0.5

2.4

4

0.8

3.2

5

1

4

6

1.2

5

8

1.6

6.5

10

2

8.5

12

2.35

10

Middle

-

-

12

-

-

Data Processing:   Conclusion:

From the three graphs above it can be seen in all of them that there is a firm relationship between the two factors, one being voltage and second one being current. Therefore I have accomplished my aim, as I have found what is the relationship between the current through a resistor and the voltage across it. The relationship as can be seen from the graph is positive, and thus directly proportional. This can be seen from the graph itself, because firstly, the best-fit line is a straight line going through all the points, in a positive direction. Secondly, it is proportional because the graph is going through the origin.

If we carefully look at the graph, and the results we can see that if the voltage divides the current in each specific wire, the number comes the same. In 1826, George Ohm had conducted several experiments with different metal wires to discover how the current through each depended on the voltage applied across its ends.

Conclusion

(for error 5) before starting the experiment, it could be kept in mind to keep the wire the same length by measuring it.

Above I have written the ways to improve some of the errors. Error 2 cannot be improved, upon because the school doesn’t have a voltmeter/ammeter which could go above a specific range and thus it didn’t give us specific results for the thick wire we wanted. Error 3 cannot be improved upon because keeping the temperature constant with so many people in the room is not possible. Error 4 cannot be improved upon as there always has to be some human error. No human is 100% perfect, and thus not all errors can be removed. But they can be improved upon, and reduced to a certain limit.

To further extend this experiment, we could do the following:

• Use a variety of thickness of wires.
• Using other materials other than a Nichrome Wire in order to test resistance.
• Testing other variables like the effect of temperature on resistance.
• By improving upon the errors.

-  -

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

# Related AS and A Level Electrical & Thermal Physics essays

1.  ## Measurement of the resistivity of Nichrome

5 star(s)

Therefore R1 /R2 = d12 /d22 Rearrange it R1 = d12 � R2 / d22 From the equation above I could get that the Rmax = dmax2�R /d2 Maximum value of percentage uncertainty of resistance (Max) = (Rmax - R)

2. ## The potato - a source of EMF

EMF: Earlier on in the theory section of my coursework I predicted that the EMF would decrease as the electrodes were brought closer together. The potato cell will have been running for some time and so I would expect the power to decrease over time.

1. ## Investigating the effect of 'length' on the resistance of a wire

* Two screws. * Two nails. * A micrometer (0-25mm). * A calculator to calculate the resistance and the mean average for each length. * Thermometer (accuracy of up to 1 d.p). The teacher supervising provided me with the required wooden plank with the ruler nailed onto it and with screws either side touching the ruler.

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

2. This case is totally wrong. If the applied force is smaller than the static friction, there will be a net force in the direction f the static friction that is opposite to the direction of the applied force. By the Newton's second law of motion, the block will move in the opposite direction of the applied force.

1. ## investigating the relationship between the diameter and the current in a wire at its ...

voltmeter while removing the problems faced by temperature on all the test wires. 'The resistance of a metal increases with an increase of temperature' (Pg.

2. ## resistivity if a nichrome wire

I will ensure that I use the same wire throughout my experiment. By doing this I have abolished any chances of having wires of different resistively, cross sectional area or densities. Equipment Faults in the equipment due to them being old or broken might affect my results.

1.  ## Resistance of a wire

* Always switch off equipment after you have finished using it or between each measurement to allow the wire to cool. * Never use faulty equipment, report it immediately to a member of staff. * Keep gangways clear of obstructions.

2. ## The varying of the resistance of nichrome wire depending on its length

Resistance is caused when they collide with atoms. Therefore, when the temperature is increased the collisions will also increasing, thus increasing the resistance. Resistors (sometimes made of a length of nichrome wire) can be used to reduce the current in a circuit. One use for a resistor is when the current flowing needs to be controlled, e.g. • Over 160,000 pieces
of student written work
• Annotated by
experienced teachers
• Ideas and feedback to 