Quiz on Chapter 5 "Using Energy"

Which of the following is a form of Energy?

Calculate how many megajoules of Energy are contained in: ( 4 800 000J )

What is Energy efficiency?

In Australia, climate change is likely to :

Improvements in house design can be achieved by:

The law of conservation of energy states that energy can never be created or destroyed. It can only get lost

The greater proportion of useful output energy, the greater the energy efficiency of the device

A car travelling down the freeway uses the heat energy in petrol to give it the kinetic energy to keep moving.

Heat naturally flows from regions of [blank_start]higher[blank_end] temperature to regions of [blank_start]lower[blank_end] temperature. In winter, the warm air from a heater or heating system can flow through [blank_start]any cracks or gaps[blank_end] in the walls to the [blank_start]cool air outside[blank_end] or into the cooler garage.Adding [blank_start]insulation[blank_end] to ceilings and between the walls of a home reduces the [blank_start]heat flowing outside[blank_end] in winter and inside in summer. This makes heating and cooling more [blank_start]effective[blank_end] and makes a house more [blank_start]comfortable[blank_end]

A [blank_start]solar cell[blank_end] converts light energy from the Sun directly into [blank_start]electrical energy[blank_end]. This [blank_start]electrical[blank_end] energy is converted into the [blank_start]kinetic[blank_end] energy of the blades, as well as [blank_start]sound[blank_end] and [blank_start]heat[blank_end] energy produced by the solar fan.

In 10 minutes, a power saw used 6050 J of electrical energy. It converted: • 1210 J into kinetic energy • 1520 J into sound energy • 3320 J into heat energy. Question (1) What is the useful output energy from the saw? [blank_start]1210J[blank_end] Question (2) What is the energy efficiency of the saw in percentage? [blank_start]1210÷6050=0.2, 0.2x100= 20%[blank_end]

An electric lamp is 25% efficient. If it receives 100 J per second of electrical energy, how much of this is transferred as light energy? [blank_start]25÷100=0.25, 0.25x100= 25J[blank_end]

The need to save energy has led to new and innovative designs to increase efficiency. Some of these ideas include

How much is one kilowatt equal to in Joules?

Greater energy efficiency is indicated by less stars (or half stars) out of a possible six stars.

Complete the following table about Energy Conversiations.

Fill in the blanks to complete the design features of this energy efficient home.

Energy transformations are shown using an arrow. Complete the following chart.

Why is it that the process of converting the chemical energy of coal into electrical energy is very inefficient ?

Most energy conversions waste some energy, usually releasing it as kinetic energy.