1-- Waves and radiation
- Created by: umar2312
- Created on: 24-04-17 21:26
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- Waves and Radiation
- Waves
- Longitudinal Wave
- A longitudinal wave is a wave in which the vibration is along the same line as the direction of travel.
- Transverse Waves
- A transverse wave is one in which the vibration is at 90 degrees to the direction of travel.
- The frequency of a wave is the number of waves that pass a point in 1 second.
- The wavelength is the horizontal distance between two adjacent troughs or peaks on the waves
- The amplitude of a wave is half the vertical distance between a trough and a crest
- A period of a wave is the time it takes for one wave to pass a point.
- Reflection is when a wave changes direction by boucing off a surface.
- Refraction occurs when a wave passes from one medium to another with a change in wave speed.
- Diffraction is the bending on the wavefront as it encounters a barrier or gap. the degree of bending depends on the size of the barrier, or gap compared to the wavelength
- interferenece occurs when two or more waves passing through the same region combine to form a resultant waveform.
- Light
- Since light is a wave it tavels in a straight line it can be reflected and refracted.
- Light is a transverse wave that doesn't require a medium to travel through..
- The law of reversibility states that a ray of light which tavels along any particular path it travel the same way back if reversed.
- A convex lens is an oval shape and causes rays of light to converge to a focal point
- A Concave length is the opposite shape and causes the rays of light to diverge.
- When light speeds up as it passes from one medium to another the direction of the ray bends away from the normal. at a certain angle of incidence he refracted wave has an angle refraction of 90 degrees
- Longitudinal Wave
- Radiation
- Types of Nuclear Radiation
- Alpha Particles
- Beta Particles
- Gamma Rays
- These are caused by the energy changes in nuclei. Often gamma rays are sent out the same time as alpha and beta
- Gamma Rays have no mass or charge and carry energy from the nucleus leaving the nucleus in a more stable state
- Low ionising ability
- Absorbed by a thick piece of lead
- Low ionising ability
- Gamma Rays have no mass or charge and carry energy from the nucleus leaving the nucleus in a more stable state
- These are caused by the energy changes in nuclei. Often gamma rays are sent out the same time as alpha and beta
- These are fast moving electrons
- They are special types of electrons as they come from the nucleus
- Medium ionising ability
- Absorbed by aluminium
- Medium ionising ability
- They are special types of electrons as they come from the nucleus
- Gamma Rays
- These are the nucei of helium atoms.
- They have 2 Neutrons and 2 Protons in the nucleus and therefore poaitively charged.
- High ionising ability
- Absorbed by skin, or a sheet of thin paper
- High ionising ability
- They have 2 Neutrons and 2 Protons in the nucleus and therefore poaitively charged.
- Beta Particles
- Alpha Particles
- ionisation is the adition or removal of an(some) electron(s) is called ionisation.
- There are some atoms which have unstable nuclei which throw out particles, or energy, to make nucleus more stable.these atoms are called radioactive.
- Radiation can be used in the treatment of cancer. The radioactive source cobalt-60 kills malignant cancer cells .
- Electromagnetic Spectrum
- In order of decreaasing wavelength, and increasing frequency and energy.
- Radio Waves
- Micro Waves
- Infared Waves
- Visible Light
- Ultra Violet
- X-Rays
- Gamma Rays
- The higher the frequency the more dangerous it is
- Gamma Rays
- X-Rays
- Ultra Violet
- Visible Light
- Infared Waves
- Micro Waves
- Radio Waves
- In order of decreaasing wavelength, and increasing frequency and energy.
- The activity of a radioactive source is the number of decays per second. (Bq)
- Tha absorbed dose is the energy absorbed per unit mass
- Background radiation comes from natural sources. EG Rocks, Cosmic rays, Building material, the human body.
- The biological effects of radiation
- All ionisng radiation can cause damage to the body. There is no minimum amount of radiation which is safe.The risk of biological harmfrom an exposure to radiation depends on :
- The absorbed dose
- The kind of radiation
- The body organs or tissue exposed
- All ionisng radiation can cause damage to the body. There is no minimum amount of radiation which is safe.The risk of biological harmfrom an exposure to radiation depends on :
- Nuclear Fission occurs when a massive unstable atomic nucleus splits into two nuclei , giving off energy and radiation
- Nuclear Fusion occurs when two atomic nuclei fuse together to form a single, large nucleus. energy is released.
- Types of Nuclear Radiation
- Waves
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