3. Physics Of Waves Flashcards
Longitudinal Waves
Direction of movement parallel/same direction to direction of oscillation.
Transverse Wave
Direction of movement perpendicular to direction of oscillation.
Example of Transverse waves
- Light
- Water
- Rope
Example of Longitudinal waves
- Sound
* Spring
Wavelength
Distance between two successive crests/troughs (Periode).
Frequency
Number of complete waves (Hertz).
Amplitude
Hight of crest/depth of trough measured at the center.
Time periode
Time taken for a wave to complete 1 cycle per wave.
Velocity
Distance traveled per second (m/s).
Wavefront
- Location of all particles of the medium in the same state of vibration.
- Perpendicular to wave direction.
- Distance from one wavefront to next is wavelength.
Properties of Reflection
Explanation: wave hits plane surface and gets reflected. •Frequency unchanged •Speed unchanged •Wavelength unchanged •Direction changes
Refraction
Bending of waves towards the normal as it enters a denser medium.
Properties of Refraction
- Angle of incident> Angle of refraction.
- Speed changes
- Wavelength changes
- Frequency unchanged
- Speed is greater in a gas (faster) than a solid (slow)
Properties of Diffraction
Explanation: wave spreads out when passing through a gap or edge of object.
•Wavelength unchanged
•Speed unchanged
•Frequency unchanged
•Wavelength = gap –> maximum diffraction.
Law of reflection
Angle of incident = Angle of refraction.
Real Image
Image that can be projected onto a screen.
Virtual Image
Image can not be projected onto a screen.
Properties of image in plane mirror
- Line joining object & image is perpendicular to the mirror.
- Same size as the object.
- Virtual image
- Inverted
Critical angle
Incident angle at which the angle of refraction is 90^•.
Monochromatic light
Light of same colour and frequency.
Compretion
Region of wave where particles are under high pressure.
Refraction
Region of wave where particles are far apart and under low pressure.
Convex / Concaving lens
Thicker at the middle than at the edges.
Concave / Diverging lens
Thicker at edges than at the middle.
Principal axis
Straight line that passes through the center of the lens.
Aperture
Diameter of lens.
Optical center
Point inside the lens situated on the principal axis. (Stipple line in lens)
Focal point / Focus
Point at which incident rays parallel to the principal axis of the lens converges or appears to diverge after refraction.
Focal length
Distance from the optical center (stipple line in lens) to the focus.
Properties of Magnified image
- Same side as object
- Virtual image
- Further from lens than object
- Upright
- Image is larger than object
Speed of light
3x10*8 m/s
Electromagnetic spectrum
- Radio waves
- Microwaves
- Infrared
- Visible light: Red, Yellow, Orange, Green, Blue, Indigo, Violet
- Ultraviolet
- X-rays
- Gamma rays
Electromagnetic spectrum span
0.0001nm-100m
Properties of Electromagnetic spectrum
- Frequency increases form Radio waves -> Gamma rays
* Wavelength increases from Gamma rays -> Radio waves
Range healthy human can hear?
20-20000Hz
Ultrasound
High frequency sound waves.
Compression (sound)
Hight pressure section of a longitudinal wave.
Rarefraction
Low pressure section of a longitudinal wave.
Pitch
Frequency
•F directly proportional to Pitch.
Loudness
Amplitude
•A directly proportional to Loudness.
Typical values of Speed of sound in solid, liquid & gases.
- Solid- 5000 m/s
- Liquid- 1400 m/s
- Gas- 330 m/s
