LIGHT+AND+SOUND

IGCSE PHYSICS > WAVES =LIGHT AND SOUND= PROPERTIES OF WAVES THE ELECTROMAGNETIC SPECTRUM INVESTIGATION OF REFLECTION USING A RAY BOX - reflection in a plane mirror. INVESTIGATION OF REFRACTION USING VARIOUS PERSPEX BLOCKS INVESTIGATION TO CALCULATE REFRACTIVE INDEX 3.14 recall that light waves are transverse waves which can be reflected, refracted and **diffracted** [|SEE WAVEFRONTS REFLECTING, REFRACTING AND DIFFRACTING] [|GOOD REFRACTION FLASH SIMULATION WITH WAVEFRONTS]



REFLECTION: Where a wave bounces of a surface. LAW OF REFLECTION: The angle of incidence equals the angle of reflection. 3.15 recall that the angle of incidence equals the angle of reflection 3.16 construct ray diagrams to illustrate the formation of a virtual image in a plane mirror

INVESTIGATION OF REFRACTION USING VARIOUS PERSPEX BLOCKS 3.17 describe experiments to investigate the refraction of light, using rectangular blocks, semicircular blocks and triangular prisms REFRACTION: Where a wave changes direction when it passes from one medium to another.





3.18 recall and use the relationship between refractive index, angle of incidence and angle of refraction. INVESTIGATION TO CALCULATE REFRACTIVE INDEX

REFRACTIVE INDEX: A constant which tells how much a medium refracts (how ‘optically dense’ it is). , where i and r are angles of incidence and refraction respectively.

3.19 describe an experiment to determine the refractive index of glass, using a glass block

3.20 describe the role of total internal reflection in transmitting information along optical fibres and in prisms



TOTAL INTERNAL REFLECTION: This happens inside a more optically dense material where all of a wave reflects from a surface and none is transmitted.



3.21 recall the meaning of critical angle c

CRITICAL ANGLE JAVA APPLET

CRITICAL ANGLE: The angle at which total internal reflection first occurs.

3.22 recall and use the relationship between critical angle and refractive index

PRACTICE QUESTIONS ON REFRACTION AND CRITICAL ANGLE (5 is difficult and optional) [|Reflection, refraction calculation practice questions.doc]

**3.23 understand the difference between analogue and digital signals.** **3.24 describe the advantages of using digital signals rather than analogue signals** **3.25 describe how digital signals can carry more information**

DIGITAL SIGNAL: A signal which can be represented as a series of 1s and 0s. it can be perfectly copied. ANALOGUE SIGNAL: A signal recorded from a real life situation. It degrades as it is copied.

3.26 recall that sound waves are longitudinal waves which can be reflected, ** refracted and diffracted **



SEE SOME OTHER COMBINED LONGITUDINAL AND TRANSVERSE WAVES

3.27 recall that the frequency range for human hearing is 20 Hz – 20 000 Hz 3.28 describe how to measure the speed of sound in air [|MEASURE YOUR HEARING] - website where you can investigate your response to different frequencies.

[|SPEED OF SOUND SIMULATION] - Click through to third page. Measure it 10 times and find the average speed

**3.29 understand how an oscilloscope and microphone can be used to display a sound wave.** [|THE VIRTUAL OSCILLOSCOPE] - learn about it by playing with it OSCILLOSCOPE: Apparatus which represents oscillations by a trace on a screen.

**3.30 use an oscilloscope to determine the frequency of a sound wave** [|LINK TO CALCULATIONS ON AN OSCILLOSCOPE SCREEN]

** 3.31 appreciate that the pitch of a sound depends on the frequency of vibration of the source ** ** 3.32 appreciate that the loudness of a sound depends on the amplitude of vibration .** PITCH AND LOUDNESS: Properties of a sound wave analogous with frequency and amplitude.

[|HOW MUSIC WORKS] - radio report from NPR (20 min)