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CCEA A Level Physics June 2015

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Original post by ccasey1995

I got the height of the screen to be like 3.63? I took the average of the three u and v values and got like 20.56 over 28.3 and then that is like 0.7 something so multiplied by 5?? Then got focal length to be 12. Wonder what we did differently?

The shortest length I got 4x10^-7m
Think I used E=hc/wavelength?

I got the level to be -1.12eV

When light goes from air to glass it bends towards the normal and then glass to air it bends away from the normal? So I thought it would bend away? It was leaving the water was it not? So it would speed up?

Posted from TSR Mobile

For the magnification question you were supposed to take the fist set of u and v values as this would give the maximum magnification of the object and so you would work out the height of this object's image by multiplying the maximum magnification by the object height and this should give you the mimic height the screen should be.
The focal length was 10.3m
The minimum length was 4x10^-7m
The level was -1.12eV

Reply 181

kennedy82

yea probably did get 4x10^-7, just thought it was very small.

if it was leaving the water, it would bend away yes.

for the height, i didn't use an average as all the u/v results were to different.

similiar, for the focal length. i worked out the focal length for each of the 3 sets of readings then took an average of f.