10 minutes maximum! (can you do it in 5?)


1. Which of these is a base quantity?
 A. current
 B. power
 C. energy
 D. acceleration


2. Which of these is a derived unit?
 A. amp
 B. kilogram
 C. joule
 D. second


3. Which of these numbers represents the prefix 'nano'?
 A. 10^{3}
 B. 10^{6}
 C. 10^{9}
 D. 10^{12}


4. 0.0004 joules can be written in millijoules (mJ) or microjoules (µJ). Whcih of these gives both conversions correctly?

Energy in mJ 
Energy in µJ 
A 
4 
400 
B 
0.4 
400 
C 
4 
40 
D 
0.4 
40 


5. A power station has an output of 2.5 GW. This is
 A. 2 500 W
 B. 2 500 000 W
 C. 25 000 000 W
 D. 2 500 000 000 W



6. A coulomb has base units of
 A. A s
 B. A s^{1}
 C. s A^{1}
 D. s^{1} A^{1}


7. A rabbit is measured running a distance of 2.5 m in 3.45 seconds. The answer for the speed should be given as
 A. 2.5 ÷ 3.45 = 0.7246 m s^{1}
 B. 2.5 ÷ 3.45 = 0.724 m s^{1}
 C. 2.5 ÷ 3.45 = 0.72 m s^{1}
 D. 2.5 ÷ 3.45 = 0.7 m s^{1}


8. The unit [kg m s^{2}] is the same as a
 A. joule
 B. kilogram
 C. newton
 D. volt


9&10. These questions are about estimating. Try to do them WITHOUT a calculator!
A star is found to have :
 Mass = 2 x 10^{27 }kg
 Radius = 1.1 x 10^{8 }m
 Volume = 1.8 x 10^{24 }m^{3}



9. The average density of the star is about
 A. 10^{57} kg m^{3}
 B. 10^{38} kg m^{3}
 C. 10^{4} kg m^{3}
 D. 10^{3} kg m^{3}



10. The surface area of the star is about
 A. 10^{17} m^{2}
 B. 10^{15} m^{2}
 C. 10^{9} m^{2}
 D. 10^{8} m^{2}



