# The affect of changing Light intensity on Resistance due to LDR

## Main Question or Discussion Point

I've got an experiment coming up where I have to find out how the resistance in a circuit changes as more layers of 'tracing paper' are added onto a LDR i.e. as more paper is added the light intensity will fall and as a result the resistance through the circuit will increase.

I am testing for up to 6 tracing papers.

A few questions if any of you could help:

On a graph of tracing paper(s) on the x axis, against resistance on the y axis, can I expect to see a straight line or more a curved graph?

How could you measure the thickness of a tracing paper (which apparatus?)

How could you test (by an experiment) that gamma rays spread out in different directions?

Thanks a lot

Mark B

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I've got an experiment coming up where I have to find out how the resistance in a circuit changes as more layers of 'tracing paper' are added onto a LDR i.e. as more paper is added the light intensity will fall and as a result the resistance through the circuit will increase.

I am testing for up to 6 tracing papers.

A few questions if any of you could help:

On a graph of tracing paper(s) on the x axis, against resistance on the y axis, can I expect to see a straight line or more a curved graph?

How could you measure the thickness of a tracing paper (which apparatus?)

Mark B
Simple. LDR, Ohm meter, tracing paper, Room with lights on ceiling. try it!

Experiment is what science is all about.

Simple. LDR, Ohm meter, tracing paper, Room with lights on ceiling. try it!

Experiment is what science is all about.
Hi there,

Could you help with the other questions if possible too?

Many thanks

M B

One way to measure the thickness of the tracing paper would be to get a big clump of it together (say like 100 sheets), measure the thickness of all of that and divide it by how many you have (in this case, 100).

It wouldn't be 100% accurate, but thats the only way I can think of doing it.

One way to measure the thickness of the tracing paper would be to get a big clump of it together (say like 100 sheets), measure the thickness of all of that and divide it by how many you have (in this case, 100).

It wouldn't be 100% accurate, but thats the only way I can think of doing it.
Hi there,

Is there any specific instrument though? Vernier callipers (sp?) I was told possibly?

Cheers