by DeepWebLabs
GATE-GE SERIES
Geo-informatics-engineering

Remote Sensing

25 previous year questions.

Volume: 25 Ques
Yield: High

High-Yield Trend

1
2026
6
2025
18
2023

Chapter Questions
25 MCQs

01
PYQ 2023
medium
geo-informatics-engineering ID: gate-ge-
For a push-broom (along-track) sensor the following are known:
Field of view (FoV) = 2 degrees
Instantaneous FoV = 1 milli-radian
Time to scan one full scanline = s
Height above ground = 100 km
The dwell time for a single pixel of this sensor is ............................. s. (Rounded off to 2 decimal places)
02
PYQ 2023
medium
geo-informatics-engineering ID: gate-ge-
Consider the Sun and the Earth as blackbodies at and temperatures, respectively. Which of the following statement(s) is/are INCORRECT?
1
Sun emits maximum energy at
2
Sun does not emit energy at microwave
3
The wavelengths of the energies emitted by the Sun are a sub-set of the wavelengths emitted by the Earth
4
Earth does not emit energy at green wavelength
03
PYQ 2023
medium
geo-informatics-engineering ID: gate-ge-

The spectral reflectance curves of three materials (A, B, and C) are shown, along with three wavelength bands X, Y, Z. Which of the following statement(s) is/are CORRECT?

1
Each of the curve is the spectral signature of the respective material
2
A sensor designed for the wavelength band ‘Y’ will best distinguish these materials in the image captured by the sensor
3
A sensor designed for the wavelength band ‘Z’ will best distinguish these materials in the image captured by the sensor
4
These curves are normally produced using a spectro-radiometer
04
PYQ 2023
medium
geo-informatics-engineering ID: gate-ge-

To visually distinguish between a river channel and a canal on an image, having similar widths and located in the same area, the most important parameter used is _______________

1
size
2
shape
3
tone
4
texture
05
PYQ 2023
medium
geo-informatics-engineering ID: gate-ge-
For a push-broom sensor, the following details are given:
Number of detectors = 3000
Height above the ground = 900 km
Swath on the ground = 30 km
The spatial resolution of the sensor is _____ m.
1
30
2
270
3
3
4
10
06
PYQ 2023
medium
geo-informatics-engineering ID: gate-ge-

In active remote sensing of Earth objects from a satellite-borne sensor, the source of the energy used for sensing, lies at the _____________

1
satellite
2
Sun
3
object being sensed on Earth
4
ground station
07
PYQ 2023
easy
geo-informatics-engineering ID: gate-ge-
Divergence analysis in classification is used:
1
to decorrelate a given set of bands used in classification
2
to logically smooth the classified image
3
to segregate mixed and homogeneous pixels
4
to evaluate statistical separability amongst class pairs
08
PYQ 2023
medium
geo-informatics-engineering ID: gate-ge-

Consider the histogram of an 8-bit image given below at (1). A piece-wise linear contrast stretch given at (2) is applied on the said image. The minimum and maximum pixel values of the image obtained after applying the given contrast stretch are ................. (minimum value) and ................. (maximum value), respectively.

1
17, 176
2
17, 120
3
20, 176
4
20, 120
09
PYQ 2023
medium
geo-informatics-engineering ID: gate-ge-

The contingency table below is obtained after an image classification. The overall classification accuracy ( ) is given as

1

2

3

4

10
PYQ 2023
medium
geo-informatics-engineering ID: gate-ge-
The following digital numbers are given for a pixel of multispectral sensor. The NDWI (normalized difference water index) for this pixel is ............................. (Rounded off to 1 decimal place).
1
0.1
2
0.2
3
0.5
4
0.4
11
PYQ 2023
medium
geo-informatics-engineering ID: gate-ge-
Consider an across-track multispectral scanner with ground pixel size of m m in the along-track and across-track directions. Which of the following statement is TRUE?
1
Aspect ratio distortion of the image will be greater than 1
2
Aspect ratio distortion of the image will be less than 1
3
There will be no geometric distortion in the image
4
Aspect ratio distortion is a type of radiometric distortion
12
PYQ 2023
medium
geo-informatics-engineering ID: gate-ge-
The purpose of thresholding in supervised classification is
1
to reject homogeneous classes
2
to correct the geometry of the image
3
to identify image speckle
4
to identify and reject pixels not belonging to pre-defined training classes
13
PYQ 2023
medium
geo-informatics-engineering ID: gate-ge-
The pixel values for a 3 band and 8-bit image are (127, 127, 127). On an RGB colour display, this pixel will appear ..............................
1
green
2
black
3
gray
4
white
14
PYQ 2023
medium
geo-informatics-engineering ID: gate-ge-
Choose the CORRECT statement(s) regarding microwave remote sensing.
1
Spatial resolution of passive microwave remote sensor is coarser than that of active microwave remote sensor from the same platform
2
The intensity of signal returned by an object depends on its geometric as well as dielectric properties
3
It is possible to “see through” the dense forest canopy using X-band active microwave remote sensing (i.e.\ signals can penetrate the dense forest canopy)
4
Microwave remote sensing can be used in soil moisture studies
15
PYQ 2023
medium
geo-informatics-engineering ID: gate-ge-
Which of the following statement(s) is/are CORRECT for sun-synchronous Earth observation satellites?
1
They are in near-polar orbit around the Earth
2
They cross the equator at different longitudes at nearly the same local solar time
3
They maintain nearly the same sun–target–satellite geometry while crossing the equator at different longitudes
4
The angle of inclination of their orbit is
16
PYQ 2023
medium
geo-informatics-engineering ID: gate-ge-
Which of the following statement(s) is/are CORRECT?
1
In optical remote sensing, more often we are interested in diffuse reflections
2
The reflection will be diffuse if the incident wavelength is comparatively much larger than the surface roughness
3
A surface that reflects microwave in specular manner may reflect the visible in diffuse manner
4
All wavelengths emitted by the Sun reflect in diffuse manner from the objects on the surface of the Earth
17
PYQ 2023
medium
geo-informatics-engineering ID: gate-ge-
The unit of spectral radiance is ...................................
1

2

3

4

18
PYQ 2023
medium
geo-informatics-engineering ID: gate-ge-
The ratio between the reflected to the incident energy on a surface at a particular wavelength gives the ............................. of the surface.
1
spectral reflectance
2
spectral transmittance
3
spectral radiance
4
spectral irradiance
19
PYQ 2025
medium
geo-informatics-engineering ID: gate-ge-

A CCD array element in a remote sensing sensor measures incoming radiation and its output voltage varies linearly between 0 V to 5 V. This voltage is converted to an 8-bit digital image using an analogue to digital convertor (ADC). The ADC has a linear response without bias or noise. If the output image pixel has a digital number of 100, the input voltage to the ADC would be _________ V (rounded off to 2 decimal places).}

20
PYQ 2025
medium
geo-informatics-engineering ID: gate-ge-
A remote sensing image is acquired from an IRS series satellite. Initially a two-dimensional filter with transfer function is applied to reduce scan line effects. Here is the distance from the center of the frequency rectangle, and is the cutoff frequency. Which one of the following will be the transfer function for the corresponding filter to detect the edges in the image?
1

2

3

4

21
PYQ 2025
medium
geo-informatics-engineering ID: gate-ge-

A CCD array element in a remote sensing sensor measures incoming radiation and its output voltage varies linearly between 0 V to 5 V. This voltage is converted to an 8-bit digital image using an analogue to digital convertor (ADC). The ADC has a linear response without bias or noise. If the output image pixel has a digital number of 100, the input voltage to the ADC would be __________ V (rounded off to 2 decimal places).

22
PYQ 2025
medium
geo-informatics-engineering ID: gate-ge-

Clouds appear white in optical visible spectral bands of remote sensing images due to _________ scattering.

1

2

3

4

23
PYQ 2025
medium
geo-informatics-engineering ID: gate-ge-
Which one of the following is NOT used to assess the quality of remote sensing image?
1
Univariate statistics of image
2
Histogram
3
Multivariate statistics of image
4
Swath of the image
24
PYQ 2025
medium
geo-informatics-engineering ID: gate-ge-
A remote sensing instrument measures only in Green, Red and Near-Infrared frequency bands. The remote sensing index/indices that CANNOT be derived using data of this instrument is/are:
1
Normalized Difference Vegetation Index
2
Atmospherically Resistant Vegetation Index
3
Soil Adjusted Vegetation Index
4
Enhanced Vegetation Index
25
PYQ 2026
medium
geo-informatics-engineering ID: gate-ge-
Which type of remote sensing system uses its own source of energy?
1
Passive remote sensing
2
Optical remote sensing
3
Active remote sensing
4
Thermal remote sensing