Energy (Overview) MCQs Quiz | Class 9
This practice quiz is designed for Class IX Science (Code 086), covering Unit III: Motion, Force and Work with a focus on Energy. The questions explore the meaning of energy, its SI unit, and basic forms including kinetic and potential energy. Complete the quiz to test your knowledge, view detailed results, and download the PDF answer sheet for your revision.
Educational Content: Energy (Overview)
1. Meaning of Energy
In physics, energy is defined as the capacity or ability to do work. An object that possesses energy can exert a force on another object to move it. Since energy is related to work, it is a scalar quantity (it has magnitude but no direction).
2. Units of Energy
The SI unit of energy is the Joule (J), named after James Prescott Joule. One joule is the energy required to do 1 joule of work. Larger units include the kilojoule (kJ).
1 kJ = 1000 J.
3. Forms of Energy
Energy exists in many different forms. The two most fundamental forms related to motion and position are:
- Kinetic Energy (KE): The energy possessed by an object due to its motion. Moving cars, running water, and wind all possess kinetic energy.
- Potential Energy (PE): The energy possessed by an object due to its position or shape (configuration). Water stored in a dam or a compressed spring possesses potential energy.
4. Mechanical Energy
The sum of the kinetic energy and potential energy of an object is known as its mechanical energy. While an object falls freely, potential energy is converted into kinetic energy, but the total mechanical energy remains constant (ignoring air resistance).
5. Other Forms of Energy
- Heat Energy: Energy transferred due to temperature difference.
- Chemical Energy: Energy stored in chemical bonds (e.g., food, batteries, fuel).
- Electrical Energy: Energy associated with the movement of electric charges.
- Light Energy: Electromagnetic radiation that is visible to the human eye.
Comparison: Kinetic vs. Potential Energy
| Feature | Kinetic Energy | Potential Energy |
|---|---|---|
| Definition | Energy due to motion | Energy due to position or shape |
| Examples | Moving ball, flowing water | Stretched bow, raised hammer |
| Dependence | Depends on mass and speed | Depends on mass, gravity, and height |
Extra Practice Questions
- Q: What kind of energy does a flying airplane possess?
A: Both Kinetic Energy (due to speed) and Potential Energy (due to height). - Q: Is work done against gravity stored as energy?
A: Yes, it is stored as gravitational potential energy. - Q: What is the commercial unit of energy?
A: Kilowatt-hour (kWh). - Q: Does a stationary stone on the ground have kinetic energy?
A: No, its velocity is zero, so KE is zero. - Q: What energy transformation happens in an electric bulb?
A: Electrical energy converts into light and heat energy.
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