EM Waves

• Radio wave:

  W.L.- >0.1m

  Freq- 3 * 10^3 to 3* 10^8
• Micro wave:

  W.L. - 0.1 m to 1mm

  Freq- 3*10^8 to 3 *10^11
• Infrared wave:

  W.L.- 1mm to 700nm

  Freq- 3 * 10^11 to 4 * 10^14
• Light:

  W.L.- 700nm to 400nm

  Freq- 4*10^14 to 8 * 10^14
• ultraviolet:

  W.L.- 400nm to 1nm

  Freq- 8*10^14 to 8 *10^16
• X-rays:

  W.L.- 1nm to 10^-3nm

  Freq- 1* 10^16 to 3 * 10^21
• Y-rays:

  W.L.- <10^-3nm

  Freq- 5* 10^18 TO 5 * 10^22
• Y-rays:

  use- penetrate thick iron; due to high energy used in nuclear reactions; destroy cancer cells

  production- Radioactive decay of nucleus

  Detection- Photographic film & ionisation chamber
• X-rays:

  Use- Medical diagnosis like fracture, TB in lungs, stone in gallbladder and kidney; to check flaws in bridges; to study crystal structure

  production- X-ray tubes; inner shell electron

  detection- Photographic films & geiger tubes
• Ultraviolet rays:

  uses- vitamin D; sterilization; detect invisible writing, forged documents, finger prints in forensic labs; preserve food

  production- inner shell electrons in atoms moving from one energy level to lower energy level

  detection- photocell; photographic film
• Infrared:

  uses- long distance photography; therapeutic purpose; green house effect

  production- by hot bodies and molecules vibration

  detection- Thermopile; bolometer' infrared photographic film
• Microwaves:

  use- RADAR system for aircrafts; homes as microwaves

  production-Special vacuum tubes like klystrons, magnetrons & gun diodes

  detection- point contact diodes
• Radio waves:

  uses- broadcasting programs to distant places

  production- rapid acceleration and de-acceleration of electrons in aerials.

  detection- receiver's aerials