Sunday 3 March 2013

3.19 describe an experiment to determine the refractive index of glass, using a glass block

Shine a ray of light through a glass block, measure the angle of incidence and the angle of refraction.
Do sin(i) divided by sin(r) and you will have the refractive index of glass.

12 comments:

  1. you can also use a graph (sin of i over sin of r) and gradient = refractive index

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  2. more detailed description of experiment if needed:
    https://theworldaccordingtohughes.wikispaces.com/describe+an+experiment+to+determine+the+refractive+index+of+glass,+using+a+glass+block

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  3. THIS IS WAY TOO VAGUE FOR AN EXAM ANSWER.
    I'VE SEEN THE EXPECTED ANSWER ON A MARK SCHEME FOR AN EXACT QUESTION LIKE THIS AND WITH AN ANSWER LIKE THAT, YOU'D GET 0 MARKS.

    A SENSIBLE ANSWER WOULD BE
    -SHINE A BEAM OF LIGHT ONTO DIFFERENT PLACES ON A RAY BOX AND MEASURE THE ANGLE OF INCIDENCE AND REFRACTION EACH TIME WITH A PRECISE PROTRACTOR. REPEATING THIS MULTIPLE TIMES GIVES YOU A RANGE OF VARIED RESULTS (ACCURACY).

    - USE THE EQUATION FOR THE REFRACTIVE INDEX (N=sin i/sin r.) TO PLOT A GRAPH OF RESULTS

    - CALCULATE THE AVERAGE OF YOUR RESULTS TO GET AN ACCURATE VALUE OF THE REFRACTIVE INDEX.

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