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). Which of these gives both conversions correctly?

A
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
 power-plant

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 1027 kg
  • Radius = 1.1 x 108 m
  • Volume = 1.8 x 1024 m3
  

9. The average density of the star is about

  • A. 1057 kg m-3
  • B. 1038 kg m-3
  • C. 104 kg m-3
  • D. 103 kg m-3

 

 

10. The surface area of the star is about

  • A. 1017 m2
  • B. 1015 m2
  • C. 109 m2
  • D. 108 m2