29/03/2020 Direct Sensing(Senior Class Physics Study by Topics) 29/03/2020 0Comments by Gate Academy Welcome to your Direct Sensing(Senior Class Physics Study by Topics) NAME EMAIL PHONE NUMBER 1. What is remote sensing? Ability to gather information about a distant or unseen target using paranormal means or extra-sensory perception Electrical impedance measuring technique that uses separate pairs of current-carrying and voltage-sensing electrodes to make more accurate measurements Allowing graphical applications to be run remotely on a server, while being displayed locally Small or large-scale acquisition of information of an object or phenomenon not in physical or intimate contact 2. Pressure measuring device consisting of a group of wires that stretch when pressure is applied. Capacitance transducer Differential pressure cell Manometer Strain gauge transducer 3. The photoconductive cell has an increase in conduction when exposed to photon energy (light) which releases free electrons. The extra free electrons lowers the resistance of the cell allowing more current flow. True False 4. What materials are reed relays made of ? Ferrous metals None of the above Non ferrous metals Insulators 5. Piezoelectric transducer is used for measuring electrical quantities non-electrical quantities chemical quantities any quantity 6. In kitchen applications a piezoelectric crystal is used for _________ lighting a gas stove skimming milk mixing grinding 7. What colour does living vegetation appears as on false-colour IR images? Black Green Blue Red 8. What does temperature coefficient mean? Change in temperature How hot the device can get before damage occurs. The temperature at which the device has zero ohms. How much the resistance, voltage or current of a device changes with heat or cold. For a thermistor it is the amount of resistance change 9. A piezoelectric transducer has a _________ high sensitivity zero sensitivity low sensitivity very low sensitivity 10. Which of the following remote sensing technologies use sound? Colour Infrared SONAR RADAR LORAN 11. What is photogrammetry? Determining the geometric properties of objects from photographic images Analysing a real-world object or environment to collect data on its shape and possibly its appearance Optical illusion of depth created from flat, two-dimensional image or images Estimating the three-dimensional coordinates of points on an object 12. Instrument used to measure the difference between two pressure points Capacitance transducer Strain gauge transducer Differential pressure cell Manometer 13. Piezoelectric transducer consists of _________ copper rod gold crystal aluminum wire quartz crystal 14. Pressure measuring device with two fluid chamber tube gauges connected by a U-shaped tube Manometer Capacitance transducer Strain gauge transducer Differential pressure cell 15. The following are true about temperature coefficient except Photoconductive cells should have zero temperature coefficient. Thermistor can have either a positive or negative temperature coefficient determined by the method and type of material used. Resistors should have zero temperature coefficient. MOVs should have a high temperature coefficient. 16. The following are true except? MOVs are used to protect computers and electronics from surge voltages called spikes. MOVs are an advanced type of Varistor. Varistors are voltage dependent resistors. None of the above MOVs are used to regulate the AC line voltage if it becomes too high. 17. Piezoelectric crystals produce _________ low voltage very high voltage no voltage high voltage 18. The following are ways in which photoconductive (photo-resistors) are used except? Temperature detectors Motion detectors Light meters ecurity lights, the photoconductive cell is in series with a relay coil to control the current flow to the lamp. 19. What type of component changes its resistance with changes in voltage? As voltage increases the resistance decreases. Varistor Wire wound resistors Thermistor Photoconductive cell 20. Which of the types of waves below has the longest wavelength? Radio Waves Hertzian Waves X-Rays Gamma Rays 21. A force of 8000 N acts on an area of 400 cm2. Calculate the pressure in Pascals. 20,000 200,000 2,000 None of the above 22. Electromagnetic waves are defined to behave in the same way of which of the following waves? Transverse waves Compressional waves Longitudinal waves Mechanical wave 23. Device that contains a measurement diaphragm and capacitor plates Differential pressure cell Strain gauge transducer Manometer Capacitance transducer 24. The following are true about thermistors except None of the above Thermistors have a wide resistance range from cold to hot, very sensitive. Thermistors can be Negative or Positive Temperature coefficient. When cold Thermistors measure open and shorted when hot. 25. What type of component has a change in resistance with temperature? Varistor Thermistor Wire wound resistors Photoconductive cell 1 out of 25 Time is Up! Time's up
