Wednesday, 29 February 2012

1.2 Reflection of Waves

Reflection of wave refers to the return of all or part of the waves when they encounter an obstacle

Characteristics of reflected waves:
1. Frequency - same (because same source)
2. Speed - same (because same medium)
3. Wavelength - same (because frequency and speed are constant)

So, what is changed???

Only direction change

1.1 Understanding Waves

  • Waves transfer energy without transfering the matter.

  • In transverse waves, its particles vibrate perpendicular to the wave direction.

  • Longitudinal wave's particles vibrate parallel to the wave direction.

  • The amplitude of a wave determines its energy. Higher amplitude has greater energy.

  • Damping of wave causes decrease in amplitude & energy.

  • Waves' wavefront is always pependicular to the direction of the waves.

  • Waves undergo all of these phenomena; reflection, refraction, diffraction & interference.

  • Water,light & electromagnetic waves are transverse waves.

  • Coherent waves have same frequency ,amplitude and in phase.

  • As the frequency of a wave increases its energy increases and its wavelength decreases.

  • Shorter waves with higher frequencies have shorter periods.

  • Facts about Light Wave
    1. Light is a transverse wave
    2. Light slows down, bends toward the normal and has a shorter wavelength when it enters a higher refractive index(n) or as it moves to denser medium..
    3. Medium with higher refractive index has higher optical density.
    4. At the critical angle a light wave will be refracted to 90 degrees.
    5. Blue light has more energy,a shorter wavelength and a higher frequency than red light (remember- ROYGBIV).
    6. Monochromatic light has one color, frequency & wavelength.
    Facts about water waves
    1. Water waves moves faster at deeper region. This change in speed causes refraction of water waves.
    2. Water waves has longer wavelength at deeper region.
    3. Deeper region is less dense than shallow region.
    4. Water waves bended towards normal as it moves from deeper to shallow region.
    5. After diffraction, water waves amplitude decrease thus its energy decrease as well.However its speed, wavelength & frequency remain constant.
    Facts about sound waves
    1. Sound is a longitudinal waves.
    2. Sound is produced through vibration, thus compressing & stretching the surrounding air molecules.
    3. Louder sound has bigger amplitude.
    4. Sound with high pitch has higher frequency.
    5. The sound that we hear is known as 'audio sound' that has freuency between 20-20khz.
    6. Those sound below 20hz is known as infrasound. While sound with frequency beyond 20khz is known as ultrasonic.
    7. Sound require medium to travel. It travels fastest in solid> liquid> gas.
    8. Sound can't be heard in vacuum..Therefore..Starwars' sound effect in outer space is a myth :)

    Fizik SPM

    Format Fizik SPM

    Kertas 1 - 50 soalan objektif
    Kertas 2 - 3 seksyen iaitu A (struktur). B (esei) dan C (esei)
    Kertas 3 - 2 soalan amali bertulis