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Remote Sensing [ Question No: 1 To 4 ] :
What is the wavelength of visible region in the electromagnetic spectrum ?
Remote sensing techniques make use of the properties ...................., emitted, reflected or diffracted by the sensed objects.
Which one of the following is not a sensor of Indian remote sensing (IRS) satellite ?
What is 'SAR' in remote sensing, a technology for producing fine-resolution images from a resolution limited radar system?
Total number of questions : 4
Number of answered questions : 0
Number of unanswered questions : 4
Remote Sensing [ Question No: 1 To 4 ] :
What is the wavelength of visible region in the electromagnetic spectrum ?
Your Answer : (Not Answered)
Correct Answer : A
The visible region spans about 0.4 - 0.7 μm.
Human eyes respond to wavelengths from about 0.4 μm (violet) to 0.7 μm (red), that is 400-700 nm. In remote sensing, the blue, green and red bands of sensors all lie in this range.
0.7-1.0 μm is the near infrared, important for vegetation studies. 1.0-3.0 μm is the shortwave infrared, and 3.0-3.5 μm lies in the mid infrared. None of these is visible light.
Remote sensing techniques make use of the properties ...................., emitted, reflected or diffracted by the sensed objects.
Your Answer : (Not Answered)
Correct Answer : C
Remote sensing uses electromagnetic waves.
Remote sensing gathers information about objects without touching them, by recording the electromagnetic radiation they reflect, emit or scatter: visible and infrared light in optical sensors, thermal infrared in thermal sensors, and microwaves in radar and passive microwave instruments.
Sound waves are used in sonar and seismic surveys, not in remote sensing from aircraft and satellites. 'Electric waves' is not a separate kind of wave, and wind waves are waves on water.
Which one of the following is not a sensor of Indian remote sensing (IRS) satellite ?
Your Answer : (Not Answered)
Correct Answer : D
The sensor that is not on IRS satellites is TM.
TM, the Thematic Mapper, is the multispectral sensor of the American Landsat 4 and 5 satellites, operated by NASA and the USGS.
The other three are Indian sensors: LISS-III (Linear Imaging Self-Scanning sensor) flew on IRS-1C, 1D and Resourcesat; PAN, the panchromatic camera, also flew on IRS-1C and 1D; and WiFS, the Wide Field Sensor, gave wide-swath coverage on the same satellites.
What is 'SAR' in remote sensing, a technology for producing fine-resolution images from a resolution limited radar system?
Your Answer : (Not Answered)
Correct Answer : B
SAR stands for Synthetic Aperture Radar.
A radar's resolution depends on the size of its antenna (aperture). SAR uses the motion of the aircraft or satellite to combine echoes received along the flight path, synthesising the effect of a very long antenna and so producing fine-resolution images, day or night and through cloud.
The other expansions change 'aperture', the key word that explains the technique, and are not used terms.
Marks
Total number of questions : 4
Number of answered questions : 0
Number of unanswered questions : 4