| What is a wave? | An oscillation around a rest position, transferring energy without tansferring matter? |
| What is an oscillation? | A vibration. |
| What are parallel lines? | Lines that go in the same direction and remains a constant distance from each other, never intersecting |
| What are perpendicular lines? | Lines that intercept at right angles. |
| What are the two main waves? | Mechanical waves and transverse waves. |
| What are mechanical waves? | Waves that can't transmit through vacuums. |
| What is a medium? | Something that has particles. |
| What are longitudinal waves? | The direction of the oscillations are parallel to the direction of energy transfer.. There are compressions and rarefactions. E.g. sound waves. |
| What is a compression? | Dense areas. |
| What are rarefactions? | Less dense areas. |
| What are transverse waves? | The direction of the oscillations are perpendicular to the direction of energy transfer. E.g. light waves, electromagnetic waves and water waves. |
| What does frequency mean? | The number of waves that go past a point per second (Hz). |
| What are wavelengths? | The distance from one point on a wave to the same point on the next (λ). |
| What is amplitude? | The distance between the rest and peak. |
| What is the rest position/ equilibrium? | The undistributed position of the wave. |
| What is the equation for wave speed? | wave speed = frequency × wave length
m/s = Hz × λ |
| What do you use for investigating waves practical? | A ripple tank. |
| How do you measure the frequency with a ripple tank? | You can read it fro the signal generator or you can count the number of waves that pass a point in 10 seconds, then divide it by 10. This increases the accuracy, which can also rise by repeating it several times. |
| How do you measure the wavelength with a ripple tank? | You measure the length of 10 waves, then divide by 10. This increases the accuracy.
You then need to find the magnification (m = I ÷ A), because the water enlarges the actual wavelength.
To do this, you'd measure the length of another object (e.g. 13.5cm), then measure the length of the image projected (e.g. 21.5cm).
Then, you'd do the image size ÷ actual size (e.g. 21.5 ÷ 13.5) to get the magnification (e.g. x1.6).
Then, you would divide your wavelength by the magnification (e.g. 5 ÷ 1.6 = 3.125). |
| How can you find the wave speed with a ripple tank? | You multiply the wavelength by the frequency. |
| What does it mean if a wave is absorbed? | The wave transfers energy to the materials energy store, often it's thermal energy. |
| What does it mean if a wave is transmitted? | The wave travels through a material, often leading to refraction. |
| What does it mean if a wave if reflected? | The wave is sent back away from the material. This is how echos are created. |
| What type of waves are EM (electromagnetic) waves? | Transverse waves. |
| Does the speed of EM waves differ through air or a vacuum? | No, it travels at the same speed. |
| How are EM waves catagorised? | Based on wavelength and frequency |
| What energy store do radio waves transfer energy as? | Kinetic energy stores of electrons, generating an electric current. |
| What speed do EM waves usually go? | 3 × 10⁸ m/s. |
| What is the EM spectrum? | A range of all types of EM radiation. |
| What are the radiations in the EM spectrum in order? | Radio waves, Microwave, Infrared, Visible, Ultra Violet, X-ray and Gamma. |
| What is the correlation between frequency, wavelength and energy? | The higher the frequency, the greater the energy since energy is proportional to the frequency, but the smaller the wavelength. |
| What are the 3 EM radiations that can ionise? | Ultra-violet, x-ray and gamma. |
| Why are the 3 EM radiations ionising? | Because they have a high frequency, they have a lot of energy and a small wavelength.
This means that they are small enough to interact with molecules, atoms and nuclei, ionising them because it can disturb and damage the cell. |
| What is the use of radio waves? | Long range communication since it can reflect off the ionosphere. |
| What is the use of microwaves? | Satellite/ phone communication.
Heating by interacting with fat and water. |
| What is the use of infrared waves? | Remote control communication.
Heating (grills).
Thermal imaging. |
| What is the use of visible light? | Communication (visual/ fibre optics). |
| What is the use of ultra-violet waves? | Sterilizes equipment/ water.
Detects fraud.
Production of vitamin D. |
| What is the use of X-rays? | Medical diagnosis.
Medical treatment.
Mechanical diagnosis. |
| What is the use of gamma? | Medical diagnosis.
Medical treatment. |
| How ionising and penetrating are radio waves? | It's not ionising and cannot penetrate the atmosphere. |
| How ionising and penetrating are microwaves? | It's not ionising, but it can penetrate the atmosphere. |
| How ionising and penetrating are infrared waves? | It's not ionising but it can partially penetrate the atmosphere. |
| How ionising and penetrating is visible light? | It's not ionising but it can penetrate the atmosphere. |
| How ionising and penetrating is ultra violet? | It is ionising and can partially penetrate the atmosphere. |
| How ionising and penetrating are x-rays? | It is ionising and can weakly penetrate the atmosphere. |
| How ionising and penetrating is gamma? | It is ionising and can weakly penetrate the atmosphere. |
| How are microwaves dangerous? | It can cause burning. |
| How are infrared waves dangerous? | It can cause burning. |
| How is ultra violet dangerous? | It can cause sunburn/ cancer. |
| How are x-rays dangerous? | It can cause cancer. |
| How is gamma dangerous? | It can cause cancer. |
