1. 3. a space entirely devoid of matter.
  2. 5. a material or device that conducts or transmits heat, electricity, or sound, especially when regarded in terms of its capacity to do this.
  3. 9. the property of zero electrical resistance in some substances at very low absolute temperatures.
  4. 10. the attribute of a sound that determines the magnitude of the auditory sensation produced and that primarily depends on the amplitude of the sound wave involved.
  5. 13. a periodic disturbance of the particles of a substance which may be propagated without net movement of the particles, such as in the passage of undulating motion, heat, or sound.
  6. 14. the process or action of bringing about or giving rise to something.
  7. 15. the measure of light power per unit area
  8. 17. a particle of electromagnetic radiation, or quantum of light.
  9. 19. the maximum distance a particle moves from its starting point in a wave.
  10. 20. the SI unit of electrical resistance, expressing the resistance in a circuit transmitting a current of one ampere when subjected to a potential difference of one volt.
  11. 21. A phenomenon that occurs when a wave changes direction as a result of a change in wave speed at different points along a wave front.
  12. 25. a subatomic particle of about the same mass as a proton but without an electric charge, present in all atomic nuclei except those of ordinary hydrogen.
  13. 27. the number of wave cycles to pass a point given per unit of time.
  14. 28. the bending of a wave around the edges of an opening or an obstacle.
  15. 29. the SI unit of frequency, equal to one cycle per second.
  16. 30. a substance which does not readily allow the passage of heat or sound.
  1. 1. a solid substance that has a conductivity between that of an insulator and that of most metals, either due to the addition of an impurity or because of temperature effects. Devices made of semiconductors, notably silicon, are essential components of most electronic circuits.
  2. 2. the process of removing the excess charge on an object by means of the transfer of electrons between it and another object of substantial size.
  3. 4. a device used to store an electric charge, consisting of one or more pairs of conductors separated by an insulator.
  4. 6. The process by which an object heats another object through electromagnetic waves.
  5. 7. the SI unit of electromotive force, the difference of potential that would drive one ampere of current against one ohm resistance.
  6. 8. the time it takes for a particle or physical quantity to move through one cycle of oscillation in a wave
  7. 11. the study of stationary electric charges or fields as opposed to electric currents.
  8. 12. the type of matter through which a wave propagates.
  9. 16. the SI base unit of electrical current.
  10. 17. a point in a curve or on a graph, or a value of a physical quantity, higher than those around it.
  11. 18. the property of matter that is responsible for electrical phenomena, existing in a positive or negative form.
  12. 22. the reduction in volume (causing an increase in pressure) of the fuel mixture in an internal combustion engine before ignition.
  13. 23. a quantitative expression of the potential difference in charge between two points in an electrical field.
  14. 24. a stable subatomic particle occurring in all atomic nuclei, with a positive electric charge equal in magnitude to that of an electron, but of opposite sign.
  15. 26. a stable subatomic particle with a charge of negative electricity, found in all atoms and acting as the primary carrier of electricity in solids