Pp P1b T11 Now You See It

Speed = distance / time for echoes

Explain amplitude, frequency, wavelength and speed

X rays & Gamma destroy cells

Microwaves -internal heating

Speed = frequency x wavelength Longitudinal & transverse waves

Reflection or refraction due to changes in density

Total internal reflection in optical fibres

P1b T11 Now you see it now you don’t

Exploring inside Earth with seismic waves

Problems of predicting earthquakes & tsunamis Ultra violet

Electromagnetic waves similarity & differences Same speed in a vacuum

Dangers from waves

Ultrasound - foetus during pregnancy X ray : bone fracture Microwave monitoring rain

Advantages of digital signals

Risks from mobile phones

Light - Iris recognition

Scanning by reflection

Scanning by absorption

Advantages & disadvantages of wave technology

Infra red skin burns

Digital technology in music

Ultra violet forged money Infra red - temperature measurement