Physics: Waves & the Universe
- Created by: Lily
- Created on: 12-03-13 16:14
View mindmap
- Physics: Waves & the Universe
- WAVES
- WHAT ARE THEY? Oscillations that move + transfer energy.
- LONGITUDINAL WAVES
- EXAMPLES: Sound waves, P(primary) waves, Ultrasound waves.
- WHAT? The oscillations are parallel to the direction of the wave. Involves compressions+ rarefactions.
- TRANSVERSE WAVES
- EXAMPLES: Electromagnetic waves, S(secondary) waves & Water waves
- WHAT? Oscillations are at right angles to the direction of the wave
- ELECTROMAGNETIC WAVES (Radio, Microwave, Infra-red, Visible light, Ultraviolet, X-ray, Gamma Rays)
- All travel at the speed of light - 3x10 to the power of 8
- RWaves, MWaves, I-RED and VLight used for communication.
- WHAT CAN WAVES DO?
- DIFFRACTION
- Significant diffraction only occurs when the wavelength of the wave is same order of magnitude as the size of the gap or obstacle.
- REFLECTION
- Angle of incidence = angle of reflection
- Image produced in plane mirror = virtual, upright + laterally inverted.
- REFRACTION
- Waves not refracted if travelling along normal.
- eaves change direction when refracted in another medium
- DIFFRACTION
- WAVE SPEED = FREQUENCY X WAVELENGTH
- SOUND WAVES
- Causes VIBRATIONS in a medium = sound.
- Frequency of SW = pitch, Amplitude of SW = loudness.
- Echoes = reflections of SW
- THE UNIVERSE
- Doppler effect = source moving away from observer , so there is change in wavelength + frequency.
- Source moving AWAY = INCREASED wavelength + DECREASED frequency. OPPOSITE for moving TOWARDS.
- DE causes red-shift in galaxies, where light's wavelength increases.
- Galaxy further away = moving faster away. Gives evidence of expanding Universe.
- THE BIG BANG
- All matter focused at one super dense, super hot tiny fixed point. Point exploded, expanded + cooled to form Universe. Theory supported by red shift and CMBR.
- Galaxy further away = moving faster away. Gives evidence of expanding Universe.
- Cosmic Microwave Background Radiation (CMBR) = Form of EM radiation filling Universe. Comes from radiation present shortly after beginning of Universe.
- All matter focused at one super dense, super hot tiny fixed point. Point exploded, expanded + cooled to form Universe. Theory supported by red shift and CMBR.
- Doppler effect = source moving away from observer , so there is change in wavelength + frequency.
- WAVES
Comments
Report