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Focused topic practice

elements of remote sensing MCQs

Practise focused elements of remote sensing questions with marked answers for exam preparation and subject revision.

elements of remote sensing Mcqs
1. The interaction of the electromagnetic radiation produced with a specific wave length to illuminate a target on the terrain for studying its scattered radiance, is called____________________?
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A. Active remote sensing

B. None of these

C. Passive remote sensing

D. Neutral remote sensing

2. The refractive index of the ocean water_______________?
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A. Decreases with salinity

B. Increases with temperature

C. Decreases with temperature

D. Increases with salinity
3. An Electromagnetic wave falls on to a boundary between two losses less homogeneous media with different refractive indices, a part of the wave is reflected back to the incident medium and the rest is transmitted on to the second media. This phenomenon is known as___________________?
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A. Fresnel refraction

B. Fresnel reflection

C. None of these

D. Snells law

4. While propagating through homogeneous, isotropic media_________________?
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A. Directions of both the fields are orthogonal

B. Both the fields are at right angles to the direction of propagation

C. Both A. and B.

D. Neither A. nor B.

5. Due to scan geometry of a satellite sensor____________________?
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A. All of these

B. The off-nadir resolution is degraded

C. The ground distance swept by the senor, IFOV is proportional to sec2 of scan measured from the nadir

D. The details towards the edge of the scan get compressed

6. Pick up the correct statement from the following?
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A. All of these

B. The wave whose surface of constant phase are parallel planes, is known as a plane wave

C. The relative phase difference between the waves is important and not the absolute phase of a point on the wave

D. The surface defined by the locus of points having same phase, is called a wave front

7. Pick up the correct definition from the following with response to GIS_______________?
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A. All of these

B. The area features which are wholly contained within another area feature, is known so containment

C. Common boundary between two areas of a locality is known as adjacency

D. The geometric property which describes the linkage between line features is defined as connectivity

8. The optical property of a water body depends on ?
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A. Scattering by the suspended particulate matter

B. Absorption by the dissolved material

C. Absorption by the suspended particulate matter

D. All of these
9. Which one of the following factors does not affect the scale of the air photographs ?
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A. Focal length

B. Ground elevation

C. None of these

D. Flying height

10. Pick up the correct statement from the following?
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A. Polarising angle of glass is 57.5

B. At the polarising angle, the reflected and refracted rays are orthogonal

C. The minimum frequency of light for which no electrons are emitted, is called threshold frequency

D. All the above
11. The normal altitude of GPS satellite is about________________?
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A. 16,200 km

B. 20,200 km

C. 24,400 km

D. 36,100 km

12. The entire range of the electromagnetic spectrum spans a large spectrum of wave lengths varying from__________________?
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A. 10-10 to 106 m
13. Pick up the correct statement from the following ?
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A. All of these

B. The reference for finding the phase of a wave is taken from the previous passage through zero from the negative to the positive direction

C. Phase is usually specified by angular measure with one period being 360

D. Phase of a wave is expressed as a fraction of a period with respect to a reference

14. Which one of the following parameters is accurate for DGPS ?
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A. Positional accuracies ~ 1 2 m if rover is less than 1-2 km from the reference station

B. Positional accuracies ~ 5 10 m if rover is less than 25 km

C. Positional accuracies ~ 5 10 m if rover is less than 5-10 km from reference station

D. Positional accuracies ~ 2 5m if rover is less than 2-5 fm from the reference station

15. The ratio of the total solar radiant energy returned by a planetary body to the total radiant energy incident on the body, the called________________?
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A. Albedo

B. None of these

C. Reflectance

D. Reflectance factor

16. Repetitive observations of the same area at equal interval of time are useful to monitor the dynamic phenomena________________?
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A. Vegetative cover

B. Snow cover

C. All of these

D. Cloud evolution

17. If electric permittivity and magnetic permeability of the medium are respectively and , then the velocity (Cm) of the electromagnetic wave in the medium is given by___________________?
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A. Cm

B. Cm

C. Cm = 1/

D. None of these

18. Pick up the correct statement from the following ?
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A. The changes in the polarisation of the radiation reflected or emitted by an object, is known as polarisation variation

B. A graphical representation of spectral reflectance verses the various growth stages of a crop, depicts a phonologic pattern

C. The degree of polarisation is a characteristic of the object which helps in the identification of the object

D. All of these
19. sensor IFOV is proportional to_________________?
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A. cos2

B. tan2

C. sin2

D. sec2
20. The GPS space segment consists of Navigation Satellite Timing and Ranging whose number is_______________?
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A. 24

B. 12

C. 16

D. 8

21. For C band Synthetic Aperture Radar (SAR) with Doppler band width of 1300 Hz, the coherence length loch is_____________?
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A. 250 km

B. 500 km

C. 130 km

D. 230 km
22. The arrangement of terrain features which provides attributes: the shape, size and texture of objects, is called_________________?
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A. Temporal variation

B. None of these

C. Spectral variation

D. Spatial variation
23. Coherence of two electromagnetic waves takes place if their phase difference is_________________?
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A. Constant in time and space

B. Constant in space

C. None of these

D. Constant in time

24. If flying height of a spacecraft is H, the length of air base is B and the parallax difference between two points is dp, then the difference in height___________________?
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A. h = (B/H) dp

B. h = (H/B) dp

C. h = dp/(H/B)

D. h = dp/(B/H)
25. Who coined the term, Remote sensing_______________?
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A. Evelyn L. Pruitt, a geographer

B. None of these

C. Gaspard Felix Tournachon, a French scientist

D. Wilbur Wright, an Italian scientist

26. Which one of the following helps to identify the objects on the earth surface ?
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A. Atmospheric window

B. None of these

C. Signature

D. Radiometric error

27. DGPS is based on the concept that bias errors in the position of locations in a given local area, are same if their distances are within___________________?
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A. 50 km

B. 75 km

C. 25 km

D. 100 km
28. Which one of the following quantities forms the basis of radiometry ?
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A. Radiant energy (Q)

B. All of these

C. Radiant intensity (I)

D. Radiant flux (?e )

29. In GPS, receivers used are___________________?
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A. Mechanical clocks

B. Quartz clocks

C. Atomic clocks

D. Electronic clocks

30. A and B are two towers of equal height diametrically opposite on either side of the nadir point, at 3 km and 5 km distances. Which one of the following statements is correct?
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A. Height displacement of B will be less than that of A

B. Height displacement of A will be less than that of B

C. Height displacement of A and B is equal

D. Height displacement of A and B will be towards each other

31. Which one of the following geometric errors of satellite sensors is random ?
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A. Earth rotation

B. Altitude variation

C. Scan skew

D. Panoramic distortion

32. Which one of the following errors is produced by platform characteristics of the sensor ?
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A. All of these

B. Altitude variation

C. Altitude

D. Orbit drift

33. The instruments which provide electromagnetic radiation of specified wave length or a band of wave lengths to illuminate the earth surface are called________________?
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A. None of these

B. Passive sensors

C. Active sensors

D. Sensors

34. Pick up the correct statement from the following ?
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A. All of these

B. The refractive index of a medium varies according to the wavelength of the radiation,

C. The splitting of colours of white light by passing through a prism is caused due to dispersion

D. The variation of the refractive index with wave length, is called dispersion,

35. Leaf reflectance depends primarily on______________?
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A. The pigments

B. Internal cell structur

C. All of these

D. Equivalent water content

36. Which one of the following statements is correct regarding the GPS satellites ?
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A. All of these

B. The satellite transmits two L band signals (L1 with 1575.42 MHz and L2 with 1276.6 MHz)

C. The nominal altitude is about 20,200 km

D. The inclination of axis satellite is 55

37. Pick up the correct statement from the following ?
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A. Platforms may be either stationary or mobile

B. All of these

C. In remote sensing technique, the observation place, is called a platform

D. Spatial resolution of the imaging system becomes poorer with increase of platform height

38. Pick up the correct statement from the following ?
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A. Indian space effort started in 1962 with the establishment of a rocket

B. Indian Space Research Organisation (ISRO) is responsible for the space technology and its application to various activities

C. All of these

D. Development of space (DOS) was established by the Government of India in 1972

39. Electromagnetic radiation_______________?
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A. Produces a time varying magnetic field and vice versa

B. Is capable to travel across space

C. Once generated, remains self-propagating

D. All of these
40. The object of photo-interpretation is__________________?
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A. Identification

B. All of these

C. Recognition of objects

D. Judging the significance of objects

41. Pick up the important characteristic of a target which facilitates its identification from the following ?
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A. Temporal variation

B. Spectral variation

C. Spatial variation

D. All of these
42. Pick up the correct statement from the following?
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A. An increase of phytoplankton absorbs the bule region rapidly

B. Phytoplankton contains photosynthetically active pigment

C. An increase of phytoplankton decreases the back scattering in the green region

D. An increase of phytoplankton increases the back scattering in the green region

43. According to the Snells law if an electromagnetic wave is incident in a medium (refractive index n1) on another medium (refractive index m2)________________?
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A. The angle of incidence is equal to the angle of refraction

B. The angle of refraction r) is given by sin i

C. Both A. and B.

D. Neither A. nor B.

44. Remote sensing techniques make use of the properties of ______________ emitted, reflected or diffracted by the sensed objects?
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A. Electric waves

B. Wind waves

C. Electromagnetic waves

D. Sound waves

45. Which one of the following attributes is not associated with digital maps_______________?
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A. Legends

B. Symbology

C. South arrow

D. Colour

46. The coherence length over which there is a strong relationship between amplitudes is_________________?
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A. None of these

B. Inversely proportional to the bandwidth

C. The square of the bandwidth

D. Directly proportional to the bandwidth

47. Pick up the correct statement from the following ?
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A. For the same feature, the photograph taken from the satellite vertically above the aircraft, the height displacement is lesser than the aerial photograph

B. The scale of the aerial photograph depends upon the scale of the topography

C. The feature at the principal point has no height displacement

D. All of the above
48. Which one of the following residual biases involves the GPS accuracy ?
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A. Satellite dependent biases due to uncertainty in the orbital parameters of the satellite

B. Receiver -dependent biases due to clock stability with line

C. All the above

D. Signal propagation biases due to the sphere and troposphere propagation

49. A passive sensor uses ________________?
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A. Flash light as a source of energ

B. Its own source of energy

C. Sun as the source of energy

D. None of these

50. Which one of the following parameters is considered to determine the reflectance of a vegetation canopy ?
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A. Solar zenith angle

B. All of these

C. Azimuth angle

D. Look angle