Specification reference Checklist questions

Analysis

1. 
   What is the uncertainty in your measurements of the independent variable?
   
2. 
   How many values did you use for the independent variable?
   
3. 
   Was this enough values? Explain your answer.
   
4. 
   What would increasing the number of values used do to your results?
   
5. 
   What is the uncertainty in the value of θ₂ when θ₁ = 60°?
   
6. 
   Calculate this as a percentage of the mean value of θ₂ at this value of θ₁.
   
7. 
   What is the uncertainty in the value of θ₂ when θ₁ = 20°?
   
8. 
   Calculate this as a percentage of your smallest value of θ₂.
   
9. 
   Use your graph to comment on the reliability of your results.
   
10. 
    Calculate the gradient of the line of best fit.
    

The refractive indices of material 1 and 2 are linked by the equation .

11. 
    Rearrange this to show the equation of your line of best fit.
    
12. 
    If material 1 is air (n₁ = 1) what does the gradient represent?
    
13. 
    Use your gradient to find the refractive index of Perspex.
    
14. 
    What is the difference between your value and the accepted value of 1.48?
    
15. 
    Calculate this as a percentage of the accepted value.
    
16. 
    What does this percentage tell you about your results?
    
17. 
    Using a sharp pencil rather than a blunt pencil did what to your results?
    
18. 
    Give some of the advantages of using a laser instead of a filament bulb.
    

Analysis

Finding the Refractive Index

You are going to use experimental data on light being shone through a Perspex block to find its refractive index.
The incident angle is measured from the normal in the Perspex block and the refracted angle is measured from the normal out of the block in the air.


Experimental Data
The protractor used to measure the incident and refracted angle had a precision of 0.5°