waves

Waves

2 types of waves

Mechanical:

⁃ it is slow

⁃ Needs medium

⁃ Can’t travel through space

⁃ Transverse and longitudinal

⁃ Ex: SOUND and WATER

Electromagnetic:

⁃ Doesn’t need medium

⁃ Can travel through space

⁃ Fast (3.0 X 10 ttpo 8)

⁃ Only transverse

⁃ Ex: LIGHT

Transverse:

⁃ Perpendicular to the direction of wave

⁃ Seismic S-waves(secondary)

Longitudinal:

⁃ Parallel to direction of waves

⁃ Seismic P-waves(primary)

Wave properties:

0. Amplitude= highest point of wave

0. Wavelength= the length between to of the same points of a wave. EX: crest to crest

0. Periodic time: time to make one wave—> t/1

0. Frequency= number of waves in one sec—>no. Of waves/time

0. Wave SPEED= distance covered by wave in one sec—> HZ*WL

Light and sound refraction: V IMP

Light:

⁃ ⁃ ⁃ ⁃ ⁃ as go from G to S, the speed decreases, so it refracts towards the Normal

Sound:

⁃ ⁃ ⁃ ⁃ ⁃ as you go from G to S, the speed increases, so it refracts further from the Normal

EM SPECTRUM uses: RMI…VUXG

0. Radio waves: broadcasting radio and television

0. Microwaves: heating food, wireless internet,

0. Infrared waves: remote controls, night vision, intruder alarm

0. Visible light:vision

0. Ultraviolet:sterilize water, detect fake bank notes, vitamin D

0. X-rays:medical imaging of bones, security checks at airport

0. Gamma rays:cancer treatment, sterilize food and surgical tools

EM SPECTRUM DANGERS:

0. 0. Radio waves: none

0. Microwaves: brain damage

0. Infrared waves:skin burn

0. Visible light:skin burn

0. Ultraviolet:blindness, skin cancer

0. X-rays:gene mutation, cancer and cell damage

0. Gamma rays: cell damage

Properties of image formed by mirror:

⁃ upright

⁃ Same size of object

⁃ Distance between object and mirror= distance between image and mirror

⁃ Virtual

⁃ Image is behind the mirror

Dispersion:V IMP

Red: longest WL and smallest HZ and fastest and refracts least

Violet:shortens WL and Biggest HZ and slowest and refracts most.

Lenses:

Look in classified/questions

Conditions of echo:

⁃ Reflecting wall should be large

⁃ Distance between source of sound and Wal should be large

⁃ Nothing should be in the way