Curriculum
Course: IB Physics HL
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Curriculum

IB Physics HL

Theme A — Space, Time and Motion

0/125 Dr Dabour Hub Science Diagram and Course Material

Theme B — The Particulate Nature of Matter

0/105 Dr Dabour Hub Science Diagram and Course Material

Theme C — Wave Behaviour

0/73 Dr Dabour Hub Science Diagram and Course Material

Theme D — Fields

0/77 Dr Dabour Hub Science Diagram and Course Material

Theme E — Nuclear and Quantum Physics

0/89 Dr Dabour Hub Science Diagram and Course Material

Tools and Inquiry — IB Physics skills

0/43 Dr Dabour Hub Science Diagram and Course Material
Quiz

A.3.9 Efficiency Formula – Check yourself

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  • Questions count: 6
  • Passing grade: B+
  • Time limit: 10 minutes
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1.
A machine takes 500 J and delivers 350 J of useful work. Its efficiency is
0.30
0.70
1.43
0.15
2.
A motor of efficiency 80 % must deliver 400 W of useful power. The input power is
320 W
400 W
500 W
800 W
3.
Two machines of efficiency 0.80 and 0.50 are used in series. Overall efficiency is
0.65
1.3
0.40
0.30
4.
Which value for the efficiency of a device is impossible (for a normal device)?
0.05
0.95
1.05
0.50
5.
A lamp uses 40 W and is 15 % efficient in producing light. Wasted power is
6 W
34 W
15 W
25 W
6.
Which change would improve the efficiency of a pulley system?
Adding a heavier load
Lubricating the pulley bearings
Lifting the load faster
Using a thicker rope
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Part of Theme A — Space, Time and Motion — see every lesson and quiz in this unit.
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