Chapter 4 Multiple choice questions

. Section 4.2 describes kinetic and potential energy. In gravitational potential energy terms, roughly how large is a joule?

A 0.1 kg apple moved upwards through 1 metre.

A 1 kg weight moved upwards through 1 metre.

A pound weight moved upwards through 1 foot.

. Kinetic energy is energy due to motion. If the speed of an object doubles, by how much does its kinetic energy change?

It doubles.

It increases by a factor of 4.

It increases by a factor of 8.

. Box 4.2 describes the potential power from a wind turbine. If the wind speed was to double, by how much would the power in the wind increase?

A factor of 2

A factor of 4

A factor of 8

A factor of 10

. Section 4.3 describes heat energy. How many kilojoules of heat are required to make a 0.3 kg cup of coffee? Box 4.4 gives the specific heat of water as 4200 joules per kilogram per kelvin (or degree C). Roughly how many kilojoules of heat are needed to raise 0.3 kg of water from room temperature, 20 degrees C, to 100 degrees C (but without boiling it)?

20 kJ

100 kJ

1000 kJ

2000 kJ

. Section 4.4 describes electrical energy. What is the formula relating electrical resistance, R, to the applied voltage, V, and the current, I?

R = V ⨯ I

R = V / I

R = V² + I

. What is the formula relating electrical power, P, to voltage, V, and current, I?

P = V² + I

P = V / I

P = V ⨯ I

. Electromagnetic radiation is described in Section 4.5. A certain photocell is only sensitive to radiation whose wavelength is less than 0.8 micrometres. In which part of the spectrum is that wavelength?

Ultraviolet

Visible light

Infrared

. Section 4.6 describes chemical energy. The periodic table arranges different elements in columns with similar chemical properties. Which element is immediately below carbon in the table?

Oxygen (O)

Sulfur (S)

Silicon (Si)

. Box 4.9 in Section 4.6 describes the combustion of a fuel. Propane is a gaseous fuel similar to methane. A propane molecule consists of three carbon and eight hydrogen atoms. An oxygen molecule contains two atoms.
How many molecules of oxygen will be needed for the complete combustion of one molecule of propane?

3

4

5

6

. Section 4.6 also describes the nuclear atom and isotopes. A carbon 13 nucleus is heavier than a carbon 12 nucleus. What makes up the weight difference?

An extra neutron

An extra proton

Many more electrons

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