WAVES
  1. A disturbance which propagated energy from one place to another ithout transport of matter - Wave
  2. A wave in which the particles of the medium vibrate in a direction perpendicular to the direction of propagation of wave - Transverse wave.
  3. A wave in which the particles of the medium vibrate in a direction parallel to the direction of propagation of wave - Longitudinal wave.
  4. The propagation of disturbance produced on one part of a medium by the vibration of its particles to all aother parts - Wave motion.
  5. The distance between two consecutive particles which are at the same phase of vibration - Wave length.
  6. Number of vibration in one second - Frequency
  7. Maximus displacement of a particle from its mean position - Amplitude.
  8. Wave travelling through layers of earth due to big explosions, earthquakes and volcanic explosions - Seismic waves.
  9. Scientist dealing with the study of seismic waves - Seismologist. 
LASER
Fig.1 - LASER

  1. LASER - Light Amplification by Stimulated Emission of Radiation.
  2. LASER is a source of coherent and intense monochromatic light ( only one wavelength or colour ).
  3. LASER was discovered by Theodore Maiman.
  4. The name LASER was suggested by Gorden Gould.
  5. In a LASER all the atoms emit the the light waves of same frequency, same amplitude, same phase.
  6. LASER beams are used in the medical field.
  7. World's sharpest laser was developed by - Germany.
  8. Radition used in the digital sound recording - Laser.
MASER
  1. MASER - Microwave Amplification by Stimulated Emission of Radiation.
  2. MASER was discovered by Charles H. Towns.
RADAR


Fig.2 - RADAR

  1. RADAR is Radio Detection And Ranging.
  2. RADAR is a device that uses radio waves to detect the position of objects such as aeroplane, missile etc.
  3. Radar was invented by Albert H. Taylor and Leo C. Young.
  4. Radio signals travel at a speed of 3x10^8 m/s.