Chapter 7: Conservation of energy

Fill in the blank: The law of conservation of energy explains that total energy is maintained in energy transfer and ________ in a system.

• transformation

• evaporation

• condensation

• decomposition

In energy transfer and transformation, the amount of usable energy is always 100% efficient.

• True

• False

Which two models are used to describe energy transfer?

• Wave and particle models

• Thermal and chemical models

• Magnetic and electric models

• Nuclear and gravitational models

What law is applied to analyse system efficiency?

• The law of conservation of energy

• The law of conservation of mass

• The law of inertia

• The law of universal gravitation

Laptops and phones get hot while charging because:

• energy is lost as heat during charging

• the battery is cooling down

• the device is not working

• charging uses cold air

What is the definition of energy? Fill in the blank: Energy is the ability to ______ or cause a change in the shape of an object (do work). Measured in joules.

• move

• sleep

• eat

• rest

Fill in the blank: Electromagnetic radiation is energy that can travel without the need for any ______ to pass through.

• material

• liquid

• sound

• light

Fill in the blank: Potential energy is energy that is ______ in a material or object.

• stored

• moving

• lost

• created

Fill in the blank: Kinetic energy is energy that an object or particle possesses due to its ______.

• motion

• temperature

• color

• size

Which of the following is an example of electromagnetic radiation?

• Sound

• Light

• Elastic

• Chemical