Understanding Energy Transformations

Which of the following is an example of chemical energy being transformed into thermal energy?

• A wind turbine generating electricity

• A battery powering a torch

• Burning wood in a fireplace

• A solar panel absorbing sunlight

Answer explanation

Burning wood in a fireplace transforms chemical energy stored in the wood into thermal energy (heat) as it combusts, making it the correct example of this energy transformation.

In a coal-fired power station, what is the initial form of energy?

• Electrical energy

• Kinetic energy

• Chemical energy

• Nuclear energy

Answer explanation

In a coal-fired power station, coal contains stored energy in the form of chemical energy. When burned, this chemical energy is converted into thermal energy, which is then used to generate electricity.

What type of energy transformation occurs in a solar panel?

• Thermal energy to electrical energy

• Light energy to electrical energy

• Chemical energy to electrical energy

• Kinetic energy to electrical energy

Answer explanation

Solar panels convert light energy from the sun into electrical energy through the photovoltaic effect, making 'Light energy to electrical energy' the correct transformation.

Which energy transformation occurs when you eat food and then go for a run?

• Chemical energy to kinetic energy

• Thermal energy to chemical energy

• Electrical energy to kinetic energy

• Light energy to thermal energy

Answer explanation

When you eat food, your body converts the chemical energy stored in the food into kinetic energy, which powers your muscles during a run. Thus, the correct transformation is chemical energy to kinetic energy.

What is the energy transformation in a battery-powered torch when it is turned on?

• Electrical energy to light energy

• Chemical energy to light energy

• Kinetic energy to electrical energy

• Thermal energy to light energy

Answer explanation

In a battery-powered torch, the chemical energy stored in the battery is converted into light energy when the torch is turned on, making 'Chemical energy to light energy' the correct transformation.

Which of the following devices transforms electrical energy into sound energy?

• A refrigerator

• A television

• A speaker

• A fan

Answer explanation

A speaker transforms electrical energy into sound energy by using electromagnetic principles to create vibrations in the air, producing sound. In contrast, a refrigerator, television, and fan serve different functions.

What type of energy transformation occurs in a wind turbine?

• Kinetic energy to electrical energy

• Chemical energy to thermal energy

• Thermal energy to electrical energy

• Nuclear energy to kinetic energy

Answer explanation

In a wind turbine, kinetic energy from the wind is transformed into electrical energy as the blades spin and drive a generator, making 'kinetic energy to electrical energy' the correct choice.

Which energy transformation occurs in a car engine that uses fuel?

• Electrical energy to kinetic energy

• Chemical energy to kinetic energy

• Thermal energy to electrical energy

• Light energy to chemical energy

Answer explanation

In a car engine, fuel undergoes combustion, transforming chemical energy stored in the fuel into kinetic energy, which powers the vehicle's movement. Thus, the correct transformation is chemical energy to kinetic energy.

Which of the following is an example of potential energy being transformed into kinetic energy?

• A book falling off a shelf

• A car accelerating on a highway

• A light bulb being turned on

• A windmill generating electricity

Answer explanation

A book falling off a shelf demonstrates potential energy converting to kinetic energy as it falls due to gravity. The height of the shelf provides potential energy, which transforms into kinetic energy as the book accelerates downward.

What type of energy transformation occurs in a geothermal power plant (where heat from the Earth is used to make power)?

• Thermal energy to electrical energy

• Chemical energy to thermal energy

• Kinetic energy to electrical energy

• Light energy to chemical energy

Answer explanation

In a geothermal power plant, heat from the Earth (thermal energy) is used to generate electricity, transforming thermal energy into electrical energy. This makes 'thermal energy to electrical energy' the correct choice.