Basic Education Certificate Examination · Integrated Science

Cycles, Energy, Machines and Forces

35 practice questions, each with the answer and an explanation.

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Random questions from this topic, one at a time. You see the answer and the explanation straight after each one.

All 35 questions

  1. Which step in the hydrological (water) cycle involves the loss of water vapour from plant leaves into the atmosphere?
  2. What term describes the continuous process by which liquid water changes into invisible water vapour at ambient temperatures?
  3. In the carbon cycle, which natural biological process removes carbon dioxide directly from the atmosphere?
  4. Which group of soil microorganisms converts atmospheric nitrogen into nitrogenous compounds usable by plants?
  5. What form of potential energy is stored in the chemical bonds of firewood, food, and petroleum fuels?
  6. What is the energy conversion that takes place when an electric blender is plugged in and switched on?
  7. By which primary mechanism is thermal heat transferred along a solid metal rod from the heated end to the cooler end?
  8. How does heat energy from the Sun travel across millions of kilometres of empty outer space to reach the Earth?
  9. Why is the heating element of an electric kettle placed at the very bottom of the appliance rather than at the top?
  10. What is the SI unit of electrical resistance named after the German physicist Georg Ohm?
  11. According to Ohm's law, which mathematical formula represents the relationship between voltage (V), current (I), and resistance (R)?
  12. What happens to the remaining electric bulbs connected in a series circuit if one bulb burns out (blows)?
  13. Why are domestic household appliances in Ghana and elsewhere wired in parallel rather than in series?
  14. What safety device in an electrical plug or consumer unit contains a thin metal wire designed to melt when current exceeds safe limits?
  15. In a simple lever, what is the mechanical advantage (MA) if an effort of 20 N lifts a load of 80 N?
  16. In a simple machine, what is the velocity ratio (VR) if the effort moves through 15 m while the load moves through 3 m?
  17. If a machine has a mechanical advantage of 3 and a velocity ratio of 4, what is its percentage efficiency?
  18. Which class of lever has the fulcrum (pivot) situated between the effort and the load, like a pair of scissors or a crowbar?
  19. A wheelbarrow, where the load lies between the wheel (fulcrum) and the handles (effort), belongs to which class of lever?
  20. How much work is done when a horizontal force of 50 N moves a wooden crate across a distance of 4 metres?
  21. What is the mechanical power developed if an electric motor performs 1,200 Joules of work in 30 seconds?
  22. What is the pressure exerted on the floor by a wooden box weighing 600 N with a contact base area of 2 m²?
  23. Why do tractors and heavy agricultural bulldozers use very wide tires or continuous caterpillar tracks?
  24. What type of friction opposes the initiation of motion between two dry stationary surfaces in contact?
  25. Which of the following practices is an effective engineering method for reducing unwanted friction in machine bearings?
  26. What is the force of gravity (weight) acting on a 15 kg student on Earth where acceleration due to gravity g = 10 m/s²?
  27. What is the fundamental difference between the mass of an object and its weight?
  28. Which property of a physical body describes its tendency to resist any change in its existing state of rest or uniform motion?
  29. According to the principle of conservation of energy, what happens to energy during physical or chemical processes?
  30. What type of renewable energy harnesses heat generated within the internal mantle and crust of the Earth?
  31. In a three-pin electrical plug used in Ghana, what standard international colour code designates the Earth safety wire?
  32. What is the standard colour code for the Live electrical wire in modern appliance flex cords?
  33. What is the standard colour code for the Neutral electrical wire in modern appliance flex cords?
  34. What magnetic rule states that like magnetic poles repel each other while unlike magnetic poles attract each other?
  35. Which magnetic material is categorized as 'magnetically soft', meaning it is easily magnetized and easily demagnetized?

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