1. All waves that travel through matter are called mechanical waves . 2. In a longitudinal wave, amplitude can be measured from the distance between high pressure areas of the wave called wavelength . 3. The position of a particle of matter in the absence of a wave is called the . 4. is determined by the energy of the disturbance that causes the wave. 5. The matter a wave travels through is called the material of the wave. True/False 6. In all mechanical waves, particles of the medium move up and down when the wave passes through them. True/False 7. A wave with greater energy has a larger amplitude. True/False 8. The more energy a wave has, the farther the particles of matter move. True/False 9. Wave amplitude is the maximum distance the particles of a medium move from their resting positions when a wave passes through. True/False

an obstruction

the body's situation won't change the forces are equal opposit and on the same body

scattering of light by tiny particles in air to produce the colors we see on sky, is dependent on the following factors:

(i) wavelength of light

(ii) size of the scattering particle  

(iii) distance traveled by light through the atmosphere.

according to rayleigh's law of scattering, the amount of scattering is inversely proportional to the fourth power of its wavelength. shorter the wavelength, greater is its scattering. hence violet/blue light is scattered more than red.

sun's light is a composite light ( visible light) with wavelengths in the range 400 nm (violet) to 700 nm (red). as sunlight passes through our atmosphere, the molecules of air scatter light according to their wavelengths. during sunrise and sunset, the sun's position is below the horizon. hence light from the sun travels a greater distance in the atmosphere when compared to its position a noon.

as sunlight enters the earth's atmosphere, blue light is scattered away and at the end of its journey in the sky, only red and orange wavelengths remain in the beam.

hence at sunrise and sunset, the sky appears reddish orange.