This 9th class physics chapter 5 online test covers Chapter 5 of the Class 9 Physics course, Work, Energy and Power. It has 25 multiple-choice questions, shown one at a time, and it marks itself as soon as you finish. There is no timer and no sign-up. When you press finish you get your score, and every question is shown again with your answer, the correct option and a short explanation of why that option is right. An Urdu medium version of the same test is given further down this page.
What Chapter 5 Covers
The questions are spread across the whole chapter rather than one section, so the test is a fair check of whether you are ready for a class test or the annual paper:
- Work done — W = Fd cos θ, the angle at which work is maximum, and why holding a heavy bag still does no work.
- Kinetic and potential energy — ½mv² and mgh, the energy of a bullet and of a moving truck, and what happens to kinetic energy when momentum doubles.
- Power — the watt, work done per second, one horsepower, and comparing two workers lifting the same load in different times.
- Efficiency — useful output divided by total input, and why no machine reaches 100 per cent.
- Conservation of energy — energy changing form as a ball falls, as a tyre bursts, and why a perpetual motion machine is impossible.
- Energy sources — renewable and non-renewable, wind turbines, solar cells, hydroelectric dams, geothermal energy and Salter’s duck for wave energy.
- Everyday numbers — the work done by a single heartbeat and the output of a water pump.
Revise These Before You Start
Most marks in this chapter are lost on the same few points. Read through these once before attempting the test:
- W = Fd cos θ. Work is maximum when θ = 0° and zero when θ = 90° or when there is no displacement.
- Kinetic energy = ½mv² and potential energy = mgh, with g = 10 m s⁻².
- Because kinetic energy depends on v², doubling the momentum of a body makes its kinetic energy four times larger.
- Power = work ÷ time, measured in watts, where 1 W = 1 J s⁻¹. One horsepower is about 746 W.
- Efficiency = (useful output ÷ input) × 100. A machine given 500 J that delivers 300 J is 60 per cent efficient.
- No machine is 100 per cent efficient because some energy always becomes heat and sound through friction.
How the Test Works
- 25 questions, one at a time, with Next and Previous buttons.
- No timer, so you can work a numerical out on paper before answering.
- Automatic marking the moment you finish.
- Answer review with the correct option and an explanation for every question.
- Retake as many times as you like, and your score is not stored anywhere.
Start the Chapter 5 Online Test
Chapter 5 rewards clean unit work: most of the numericals are one-step once you have the right formula and the right units. Keep a pen and rough paper beside you: the numerical questions are quick, but they are much easier to get right written down than in your head. Aim for 20 out of 25 or better before you move on to the next chapter.
Chapter 5 Online Test — Urdu Medium
Urdu medium students can attempt the same Chapter 5 test with every question, option and explanation written in Urdu. It behaves exactly like the English test above: 25 questions one at a time, no timer, and a full answer review at the end.
Mistakes Students Make in This Chapter
When you check your answer review, see whether any of your wrong answers came from these. They account for most of the marks lost in this chapter:
- Forgetting cos θ when the force acts at an angle to the displacement.
- Saying work is done when a man simply holds a heavy bag, when there is no displacement.
- Confusing energy with power, or joules with watts.
- Doubling kinetic energy when the speed doubles, instead of multiplying it by four.
- Listing geothermal or wave energy as non-renewable.
What to Do After the Test
Do not close the page as soon as you see your score. Read the explanation under every question you got wrong, then open that topic in your textbook and work through the solved example beside it. Write the questions you missed on a single sheet and attempt the test again the next day: the second score tells you what you have actually learned, while the first only tells you what you recognised. If you scored below 15, work through the chapter again before moving on, because the later chapters in Physics build directly on this one.
Frequently Asked Questions
Is work done when you hold a heavy bag without moving?
No. Work needs displacement in the direction of the force. Your muscles tire because they keep contracting, but in physics the work done on the bag is zero because it does not move.
Why can no machine be 100 per cent efficient?
Because part of the input energy always turns into heat and sound through friction between moving parts. That energy still exists, so energy is conserved, but it is no longer useful output.
What is one horsepower in watts?
One horsepower is about 746 watts. It is an older unit still used for engines and pumps, while the SI unit of power is the watt, which is one joule per second.
Related Class 9 Physics Resources
Work through the Chapter 5 exercise short questions for written practice. The Chapter 5 constructive questions cover the longer, reasoning-based answers. You can also browse all Class 9 Physics exercise short questions and constructive questions, or open the Class 9 Physics section, which brings notes, test papers, online papers, guess papers and past papers together chapter by chapter.