Answers to AQA GCSE Efficiency - Science Worksheets

Answers to AQA GCSE Efficiency(Physics)

Answers to Practice Questions

1.The electric motor in a fan will transfer 300J of chemical energy mechanically to 225J of kinetic energy, the remaining 75J of energy is transferred by radiation to the thermal energy store of the surroundings. Calculate the efficiency of the fan.

Input energy = 300J,

Useful output energy = 225J

Wasted output energy = 75J

2. A wind turbine will transfer 1.0 x 10⁶J of kinetic energy electrically into 600,000J of chemical energy to charge up a battery. The remaining energy is transferred by radiation to the thermal energy store of the surroundings. Calculate the efficiency of the wind turbine.

3. The energy used to increase the temperature of 1kg of water in a kettle is 2 x 10⁶J. The kettle has a rated efficiency of 80%.
Calculate the input energy that the kettle requires.

Efficiency = 80%

Useful output energy = 2 x 10⁶J

4. An electric motor uses a power of 150W to raise an object in height. 100J of work is done on the object over 0.8 seconds. Calculate the efficiency of the electric motor.

Input power = 150W

Energy

Energy stores and systems notes and questions

Real life energy transfers

Gravitational potential energy

Elastic Potential energy

Changes in energy, Specific heat capacity

Conservation of Energy

Wasted energy transfers

Energy Resources

Coal, Oil and Natural Gas

Hydroelectric, Wave and Tidal

Particle model, states of matter

Measuring Density

States of Matter

Changes of state

Internal Energy

Specific Heat Capacity

Specific Latent Heat

Heating and Cooling Curves

Specific heat capacity compared to Specific latent heat

Motion of gas particles

Gas Pressure and Volume

Doing work on gases

Structure of atom, Radioactivity

Structure of the Atom

Absorption and Emission of EM Radiation

Mass Number and Atomic Number

JJ Thomson and Plum pudding model

Ernest Rutherford and the Nuclear Model

Niels Bohr changing the Nuclear Model

Discovering the Proton and Neutron

Radioactive Decay

Measuring radiation from radioactivity

Radiation types and properties

Random nature of radioactive decay

Half life calculations

Radioactive contamination or irradiation

Hazards of contamination and irradiation

Studies on the effects of radiation on humans

Background Radiation

Different half lives of radioactive isotopes

Uses of nuclear radiation

Nuclear Fission

Nuclear Fission Chain Reaction

Writing nuclear fission equations

Drawing and interpreting nuclear fission diagrams

Moments and Pressure

Introduction to moments

Balancing Moments

Balancing Moments made more complex

Gears and Moments

Pressure acting on a surface

Pressure at the surface of a fluid

Pressure due to a column of liquid

Explaining pressure in a column of liquid

Atmospheric Pressure

Force and Movement

Distance and Displacement

Calculating Speed

Distance-time graphs

Velocity time graphs and acceleration

Velocity time graphs and acceleration curved lines

Velocity time graphs and calculating acceleration

Equation of Motion

Falling Objects

Terminal Velocity

Newton’s 1st Law

Newton’s 2nd Law

Newton’s 3rd law

Stopping distances

Braking distance

Momentum

Conservation of Momentum

Types of Collisions

Changes to Momentum

Designing Safety Features

Waves

Transverse Waves

Longitudinal Waves

Comparing Transverse and Longitudinal waves

Evidence for Waves

Characteristics of Waves

Measuring the speed of sound in air

Measuring the speed of ripples on the surface of the water

Changes to Sound Waves

Reflection of Waves

Reflection, Transmission and Absorption of Waves

Sound Waves and the Ear

Using Waves to explore structures

Using Ultrasound Waves for medicine

Using Ultrasound for industrial imaging

Using Echo sounding

Magnetism & Electromagnetism

Accordion Content

Space

Accordion Content