1.	Which of the following contains one fundamental and one derived unit?

A.	ampere	kilogram	
B.	ampere	coulomb	
C.	joule	newton	
D.	joule	coulomb	
(Total 1 mark)

2.	The uncertainty in the current, I, through a resistor is measured with a digital ammeter to be 0.10 A. The uncertainty in the calculated value of I2 will be in I is 1 amp
A.	1 %.
B.	2 %.
C.	5 %.
D.	20 %.
(Total 1 mark)

3.	Data analysis question.
	The photograph below shows a magnified image of a dark central disc surrounded by concentric dark rings. These rings were produced as a result of interference of monochromatic light.
		
	The graph below shows how the ring diameter D varies with the ring number n.
The innermost ring corresponds to n = 1. The corresponding diameter is labelled in the photograph. Error bars for the diameter D are shown.

(a)	State one piece of evidence that shows that D is not proportional to n.
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
(1)
 
(b)	On the graph above, draw the line of best-fit for the data points.
(2)
 
(c)	Theory suggests that D2 = kn.
	A graph of D2 against n is shown below. Error bars are shown for the first and last data points only.

(i)	Using the first graph, calculate the percentage uncertainty in D2, of the ring n = 7.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(2)
 
(ii)	Based on the second graph, state one piece of evidence that supports the relationship D2 = kn.
...........................................................................................................................
...........................................................................................................................
(1)
 
(iii)	Use the second graph to determine the value of the constant k, as well as its uncertainty.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(4)
(iv)	State the unit for the constant k.
...........................................................................................................................
...........................................................................................................................