## Elements of Remote Sensing MCQ Practice Questions (Civil) Set 4

##### Pick up the correct statement from the following:

Options are :

• The relative phase difference between the waves is important and not the absolute phase of a point on the wave
• All of these
• The surface defined by the locus of points having same phase, is called a wave front
• The wave whose surface of constant phase are parallel planes, is known as a plane wave

##### Which one of the following residual biases involves the GPS accuracy ?

Options are :

• Satellite dependent baises due to uncertainty in the orbital parameters of the satellite
• Signal propagation baises due to the sphere and troposphere propogation
• All the above
• Receiver-depandent biases due to clock stability with line

##### Which one of the following parameters is accurate for DGPS.

Options are :

• Positional accuracies ~ 1 - 2 m if rover is less than 1-2 km from the reference station
• Positional accuracies ~ 5 - 10 m if rover is less than 5-10 km from reference station
• Positional accuracies ~ 5 - 10 m if rover is less than 25 km
• Positional accuracies ~ 2 - 5m if rover is less than 2-5 fm from the reference station

Answer :Positional accuracies ~ 1 - 2 m if rover is less than 1-2 km from the reference station

##### Rayleigh's criteria for a rough surface is: (where letters carry their usual meanings)

Options are :

• h > ?/? cos ?
• h < ?/8 cos ?
• h = ?/8 cos ?
• h > ?/8 cos ?

Answer :h > ?/8 cos ?

##### Critical angle of electromagnetic radiation takes place if:

Options are :

• Angle of refraction is equal to 90°
• Angle of incidence is equal to 90°
• Angle of incidence is equal to angle of refraction
• Angle of incidence is greater than the angle of refraction

Answer :Angle of refraction is equal to 90°

##### The changes in the reflectivity/emissivity with time, is called:

Options are :

• Temporal variation
• None of these
• Spatial variation
• Spectral variation

##### Crop Acreage and Production Estimation (CAPE) was funded and taken up in 1983 by:

Options are :

• Russia
• India
• European Union
• USA

##### In GPS, receivers are used are:

Options are :

• Quartz clocks
• Electronic clocks
• Atomic clocks
• Mechanical clocks

##### Pick up the correct statement from the following:

Options are :

• The minimum frequency of light for which no electrons are emitted, is called threshold frequency
• At the polarising angle, the reflected and refracted rays are orthogonal
• Polarising angle of glass is 57°.5
• All the above

##### In case of reflection and refraction of electromagnetic radiation:

Options are :

• Angle of refraction = sum of the angles of incidence and refraction
• Angle of incidence = angle of reflection
• All the above
• Angle of incidence = angle of refraction

Answer :Angle of incidence = angle of reflection

Options are :

• 0.7 to 14 ?m
• 0.4 - 0.7 ?m
• 0.7 - 1.3 ?m
• 0.5 mm to 1m

##### Which one of the following statements is correct ?

Options are :

• ? radians equal to 180°
• The cone subtended by an area on the sphere at the centre, is called the solid angle
• The unit of the solid angle is steradian (Sr)
• All of these
• The solid angle is equal to the ratio of the area on the sphere and the square of the radius of the sphere

##### Electromagnetic spectrum contains:

Options are :

• Infrared rays (wave length < 10-4 m)
• Radio rays (wave length > 1 m)
• Ultraviolet rays (wave length < 10-6 m)
• All of these
• Gamma rays (wave length < 10-10 m)

Options are :

• 250 km
• 500 km
• 230 km
• 130 km

##### Pick up the correct statement from the following:

Options are :

• U.S.A.'s highly secret mission CORONA started the collection of intelligence photograpy in 1960
• All of these
• The United State's Explorer 6 transmitted the first picture of the earth in August 1959
• The first man-made satellite, Sputnik-l' was launched on 4th October, 1957
• Television Infrared Observation Satellite (TIROS) designed for meteorological observations, started systematic earth observations from space from 1, April, 1960

##### Spatial variation in horizontal and vertical directions, is caused due to:

Options are :

• Chemical weathering of rocks
• Physical weathering of rocks
• All of these
• Biological'weathering of rocks

##### The reflectance from a surface is called specular reflection if it follows:

Options are :

• Lambert's cosine law
• Snell's law
• All of these
• Planktan's law

##### Which one of the following statements is correct ?

Options are :

• All the above
• A map is a collection of stored, analysed data, its stored information is suitability used in making decisions
• The information system is the chain of operations
• The function of an information system is to improve ones ability to make decisions

##### The maximum sun's radiation occurs around:

Options are :

• 0.55 ? wave length
• 0.4 ?m wave length
• 0.7 ? wave length
• None of these

##### Who coined the term, 'Remote sensing' ?

Options are :

• Evelyn L. Pruitt, a geographer
• None of these
• Gaspard Felix Tournachon, a French scientist
• Wilbur Wright, an Italian sciencist

Answer :Evelyn L. Pruitt, a geographer

##### 'A time varrying electric field produces a magnetic field' This phenemenon is called:

Options are :

• Kirchoff's law
• Ampere Maxwell's law
• Hertz's law

##### Which one of the following geometric errors of satellite sensors is random ?

Options are :

• Panoramic distortion
• Scan skew
• Altitude variation
• Earth rotation

##### Pick up the correct statement from the following:

Options are :

• Phytoplankton contains photosyn-thetically active pigment
• An increase of phytoplankton increases the back scattering in the green region
• An increase of phytoplankton absorbs the bule region rapidly
• An increase of phytoplankon decreases the back scattering in the green region

Answer :An increase of phytoplankon decreases the back scattering in the green region

Options are :

• All of these

##### Earth observations from a satellite platform provides:

Options are :

• Synoptic view of a large area
• Repetitive observations of the same area with intervals of a few minutes to a few weeks
• Constant solar zenith angles and similar illumination conditions
• All of these

##### Which one of the following statement is correct ?

Options are :

• The radiant energy which falls upon a surface, is termed as irradiance
• Radiant energy expressed in Joules, is the energy associated with electromagnetic radiation
• The rate of transfer of radiant energy is called flux and is expressed in watts
• All of these
• The radiant energy which falls away from the surface is termed as radient exitance and is measured in Wm^(-2)

##### Which one of the following statement is incorrect regarding the electromagnetic radiation ?

Options are :

• These are produced by the motion of electric charge
• The changing electric fields induce the changing magnetic fields in the surrounding medium
• The oscillation of charged particles sets up changing electric fields
• None of these

Options are :

• 8
• 24
• 16
• 12

Options are :

• 75 km
• 1250 km
• 50 km
• 100 km
• 25 km

Options are :

• 1, 3
• 2, 3
• 1, 2, 3
• 1, 2