20 multiple-choice (MCQ / objective) questions from this chapter, in every exam-style shape used in the paper. Every question comes with an explanation along with the answer, so you remember why the option is correct, not just which one it is.
1 Direct Questions
Direct Questions
- 1 markWhat three elements does the definition of remote sensing mainly include?
(A) Only maps and tables(B) Surface objects, recording devices, energy waves(C) Only the sun and atmosphere(D) Only satellites and cameras - 1 markWhat is the most important natural source of energy in remote sensing?
(A) The sun(B) The earth’s core(C) The atmosphere(D) The moon - 1 markOn what basis are energy waves in the electromagnetic spectrum classified into different rays (gamma, X-ray, ultraviolet, etc.)?
(A) The colour of the wave(B) Wavelength and frequency(C) The source of the wave(D) The direction of the wave - 1 markThe visible spectrum roughly spans which wavelength range?
(A) 100-200 nanometres(B) 1000-2000 nanometres(C) 400-700 nanometres(D) 0.3-0.9 metres - 1 markWhy do turbid water bodies appear light blue in satellite images?
(A) They have no suspended particles(B) They emit only infrared rays(C) They reflect more of the blue and green regions(D) They absorb all the energy - 1 markWhich colour of rays is scattered the most by dust particles in the atmosphere?
(A) Blue(B) Yellow(C) Infrared(D) Red - 1 markAt what altitude, and with what orbital period, do geostationary satellites revolve around the earth?
(A) 100 km, 90 minutes(B) 36,000 km, 24 hours(C) 1,000 km, 12 hours(D) 700-900 km, 14 orbits a day - 1 markWhich category do INSAT series satellites belong to, and for what purpose are they used?
(A) Sun-synchronous, for Earth resources(B) Polar, for mapping(C) Geostationary, for military use only(D) Geostationary, for weather and telecommunication - 1 markBased on the form of the data output, sensors are classified into which two categories?
(A) Photographic and non-photographic digital(B) Indian and foreign(C) Active and passive(D) Large and small - 1 markIn what key way does a pushbroom scanner differ from a whiskbroom scanner?
(A) It works only at night(B) It has no detector at all(C) It is fitted only on geostationary satellites(D) It has a row of detectors instead of a rotating mirror - 1 markWhat is meant by Temporal Resolution?
(A) The capability to distinguish two closely spaced objects(B) The size of the image(C) The revisit time interval for imaging the same place again(D) The number of spectral bands - 1 markWhat is spectral resolution related to?
(A) The time interval(B) The size of the image(C) The satellite’s altitude(D) The recording power in different bands of the spectrum
2 Match the Following
Match the Following
- 1 markMatch Column A with Column B. Column A: 1) Landsat MSS 2) Landsat TM 3) SPOT HRV-I 4) IRS PAN. Column B: p) 30.00 m x 30.00 m q) 5.80 m x 5.80 m r) 80.0 m x 80.0 m s) 20.00 m x 20.00 m
(A) 1-q, 2-s, 3-p, 4-r(B) 1-s, 2-r, 3-q, 4-p(C) 1-r, 2-p, 3-s, 4-q(D) 1-p, 2-q, 3-r, 4-s - 1 markMatch Column A (interpretation element) with Column B (example). Column A: 1) Shadow 2) Texture 3) Association 4) Shape. Column B: p) Fine texture of rice/wheat crops q) Identification of the Qutub Minar r) A playground alongside an educational institution s) The linear outline of a railway line
(A) 1-q, 2-p, 3-r, 4-s(B) 1-s, 2-r, 3-p, 4-q(C) 1-p, 2-q, 3-s, 4-r(D) 1-r, 2-s, 3-q, 4-p - 1 markMatch Column A (type of resolution) with Column B (definition). Column A: 1) Spatial resolution 2) Spectral resolution 3) Radiometric resolution 4) Temporal resolution. Column B: p) The revisit time interval for imaging the same place q) Recording power in the bands of the spectrum r) Capability to distinguish two closely spaced objects s) Capability to detect fine radiance differences
(A) 1-s, 2-p, 3-r, 4-q(B) 1-r, 2-q, 3-s, 4-p(C) 1-p, 2-r, 3-q, 4-s(D) 1-q, 2-s, 3-p, 4-r
3 Arrange in the Correct Order
Arrange in the Correct Order
- 1 markArrange the following stages of remote sensing data acquisition in their correct order.
(A) Transmission to earth -> Source of energy -> Detection by sensor -> Interaction with surface -> Atmospheric propagation -> Conversion into data(B) Source of energy -> Transmission to earth -> Interaction with the earth’s surface -> Atmospheric propagation -> Detection by sensor -> Conversion into data(C) Detection by sensor -> Conversion into data -> Source of energy -> Transmission -> Interaction -> Propagation(D) Atmospheric propagation -> Interaction with surface -> Transmission -> Source of energy -> Detection -> Conversion - 1 markArrange the following regions of the electromagnetic spectrum in decreasing order of wavelength (longest to shortest).
(A) Radio waves -> Microwave -> Infrared -> Visible -> Ultraviolet -> Gamma rays(B) Visible -> Infrared -> Gamma rays -> Radio waves -> Microwave -> Ultraviolet(C) Microwave -> Radio waves -> Gamma rays -> Visible -> Infrared -> Ultraviolet(D) Gamma rays -> Ultraviolet -> Visible -> Infrared -> Microwave -> Radio waves
4 Fill in the Blanks
Fill in the Blanks
- 1 markSun-synchronous satellites are placed at an altitude of ________ km.
(A) 36,000(B) 100(C) 700 to 900(D) 10,000 - 1 markInstead of a rotating mirror, a pushbroom scanner uses a linear array of many ________.
(A) mirrors(B) detectors(C) prisms(D) films - 1 markIndia’s remote sensing data receiving station is located at ________, near Hyderabad.
(A) Shadnagar(B) Pune(C) Ahmedabad(D) Bengaluru
Answer Key and Explanations
Direct Questions
- (B) The definition includes objects on the earth’s surface, recording devices, and obtaining information through energy waves.
- (A) The sun is the most important source of energy in remote sensing; artificial energy such as a flashgun or radar can also be used.
- (B) Energy waves are grouped into gamma, X-ray, ultraviolet, visible, infrared, microwave and radio waves on the basis of their wavelength size and frequency.
- (C) The visible spectrum spans roughly 400 to 700 nanometres, divided from violet to red.
- (C) Turbid water bodies reflect comparatively more of the blue and green regions of the visible spectrum, so they appear light blue.
- (A) Dust particles scatter blue rays, so this energy never reaches the sensor.
- (B) Geostationary satellites revolve at an altitude of about 36,000 km with an orbital period of 24 hours, synchronised with the earth’s own rotation.
- (D) INSAT series satellites are in geostationary orbit and are used for weather monitoring and telecommunication.
- (A) Based on the form of the data output, sensors are classified into photographic (analogue) and non-photographic (digital) sensors.
- (D) A pushbroom scanner records the nadir view using a linear array of many detectors instead of a rotating mirror.
- (C) The pre-determined periodical interval (revisit time) at which a satellite reimages the same area of the earth’s surface is called temporal resolution.
- (D) Spectral resolution is related to the sensing and recording power of the sensor in different bands of the electromagnetic spectrum.
Match the Following
- (C) From Table 6.1: Landsat MSS = 80×80 m (r), Landsat TM = 30×30 m (p), SPOT HRV-I = 20×20 m (s), IRS PAN = 5.8×5.8 m (q).
- (A) Shadow identifies the Qutub Minar (q), Texture is the fine pattern of rice/wheat (p), Association is the educational institution-playground link (r), Shape is the railway line’s linear outline (s).
- (B) Spatial resolution = distinguishing close objects (r), Spectral resolution = recording power in bands (q), Radiometric resolution = fine radiance differences (s), Temporal resolution = revisit interval (p).
Arrange in the Correct Order
- (B) The correct order is: Source of energy -> Transmission from source to earth -> Interaction with the earth’s surface -> Propagation through the atmosphere (on the return) -> Detection by the sensor -> Conversion into data.
- (A) The correct decreasing order of wavelength is: Radio waves -> Microwave -> Infrared -> Visible -> Ultraviolet -> Gamma rays.
Fill in the Blanks
- (C) Sun-synchronous satellites are placed at an altitude of 700 to 900 km.
- (B) A pushbroom scanner uses a linear array of many detectors.
- (A) India’s data receiving station is located at Shadnagar, near Hyderabad.
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