20 extra multiple-choice questions for Geoinformatics (12th Standard Geography, Samacheer Kalvi), beyond the ones printed in the textbook — each with the correct option highlighted and a clear, worked explanation. Free to read in English and Tamil.
Q1
Which of the following is not one of the three major components of Geoinformatics?
- A. Remote sensing
- B. Geographic Information System (GIS)
- C. Global Navigation Satellite System (GNSS)
- D. PhotogrammetryCorrect
Explanation. The lesson says Geoinformatics has three major components: remote sensing, GIS and GNSS. Photogrammetry, the use of photography in surveying and mapping, appears only in the glossary.
Q2
The re-direction of electromagnetic radiation by particles suspended in the atmosphere or by large molecules of atmospheric gases is called
- A. Absorption
- B. ScatteringCorrect
- C. Refraction
- D. Recording
Explanation. Scattering is the re-direction of electromagnetic radiation by suspended particles or large gas molecules. Absorption, by contrast, is the process by which gas molecules absorb radiation in certain spectral bands.
Q3
Assertion (A): Image enhancement is not done until the image restoration processes are completed.
Reason (R): General enhancement distorts the original digital values of an image.
- A. Both A and R are true and R is the correct explanation of ACorrect
- B. Both A and R are true but R is not the correct explanation of A
- C. A is true but R is false
- D. A is false but R is true
Explanation. The book says general enhancement distorts the original digital values; therefore enhancement is not done until restoration, which makes the image resemble the original scene, is completed. R explains A.
Q4
Consider the following statements:
1. Active sensors generate and use their own energy to illuminate the target.
2. Passive solar sensors can capture data only during daylight hours.
3. Active remote sensing operates in the visible and infrared region of the spectrum.
Which of the statements given above is/are correct?
- A. 1 only
- B. 1 and 2 onlyCorrect
- C. 2 and 3 only
- D. 1, 2 and 3
Explanation. Active sensors produce their own energy and work in the microwave region, so statement 3 is wrong. Passive sensors depend on solar radiation and therefore capture data only in daylight.
Q5
QZSS, the regional navigation satellite system of Japan, has the nickname 'Michibiki'. What does Michibiki mean?
- A. Guide or show the wayCorrect
- B. Quasi-zenith orbit
- C. Restricted service
- D. Doppler effect
Explanation. QZSS is nicknamed Michibiki, meaning 'guide' or 'show the way'. It mainly uses satellites in quasi-zenith orbits and is sometimes called the 'Japanese GPS'.
Q6
The first known aerial photograph was taken in 1858 by
- A. Rifath Sharook
- B. Gaspar Felix TournachonCorrect
- C. Srimathy Kesan
- D. Abdul Kalam
Explanation. The first known aerial photograph was taken in 1858 by the French photographer and balloonist Gaspar Felix Tournachon, known as 'Nadar'.
Q7
Which remote sensing platform is a miniature remotely piloted aircraft that can operate without a runway and provide both night and day data?
- A. Balloon
- B. DroneCorrect
- C. Geostationary satellite
- D. Mobile hydraulic platform
Explanation. A drone is a miniature remotely piloted aircraft built as a low cost platform with long endurance. It can work without a runway or with a small one and can provide both night and day data.
Q8
Consider the following statements about geostationary satellites:
1. They make one revolution in 24 hours.
2. Their coverage is limited to 70 degrees N to 70 degrees S latitudes.
3. One satellite can view one-third of the globe.
4. They orbit the earth from pole to pole.
Which of the statements given above are correct?
- A. 1 and 4 only
- B. 2 and 3 only
- C. 1, 2 and 3 onlyCorrect
- D. 1, 2, 3 and 4
Explanation. Geostationary satellites orbit in the equatorial plane from west to east, once in 24 hours, covering 70 degrees N to 70 degrees S, one satellite viewing a third of the globe. Pole to pole orbits belong to polar satellites.
Q9
In which year did India launch its first geostationary satellite, APPLE?
- A. 1858
- B. 1981Correct
- C. 2015
- D. 2017
Explanation. On June 19, 1981 India launched its first geostationary satellite, APPLE, an experimental communication satellite launched by the Indian Space Research Organisation (ISRO).
Q10
Which of the following satellites belongs to the polar orbiting or sun-synchronous category?
- A. INSAT
- B. GOES
- C. IRSCorrect
- D. INTELSAT
Explanation. All remote sensing resource satellites are grouped as polar orbiting or sun-synchronous, such as LANDSAT, SPOT and IRS. GOES, INTELSAT and INSAT are geostationary satellites.
Q11
Signals intelligence (SIGINT) spy satellites, optimised for characterising ground-based radar systems or eavesdropping on communications, are also termed
- A. FerretsCorrect
- B. Keyhole
- C. Corona
- D. Transit
Explanation. The fourth basic type of spy satellite is the signals intelligence (SIGINT) satellite, also termed 'ferrets'. Keyhole is a U.S. series combining photo reconnaissance and SIGINT; Corona was an early U.S. spy satellite.
Q12
Gaofen 4, described as the world's most powerful GEO spy satellite (launched in 2015), helps which country monitor strategic foreign sites?
- A. United States
- B. Russia
- C. ChinaCorrect
- D. Japan
Explanation. The 'Do you know' box says Gaofen 4, launched in 2015, can give instant coverage of earthquake or typhoon hit areas and will also allow China to monitor strategic foreign sites.
Q13
Kalamsat, the world's lightest satellite designed by a Tamil Nadu student, weighs
- A. 24 grams
- B. 64 gramsCorrect
- C. 125 grams
- D. 240 grams
Explanation. Kalamsat weighs a mere 64 grams. It was designed by 18-year-old Rifath Sharook and his team, named after Abdul Kalam and flown by a NASA sounding rocket on 22 June 2017.
Q14
In oceanography, the measurement of the depth of water in water bodies is called
- A. Topography
- B. Photogrammetry
- C. BathymetryCorrect
- D. Lithological mapping
Explanation. Satellite remote sensing helps coastal zone management by monitoring bathymetry, the measurement of the depth of water in water bodies, along with chlorophyll content and suspended sediment.
Q15
Meta data, that is data about the data, is the key for documenting which component of GIS?
- A. Hardware
- B. Software
- C. People
- D. Methods or proceduresCorrect
Explanation. Methods are well-defined, consistent procedures needed to produce accurate, reproducible results. The book says meta data (data about the data) is the key for documenting these processes.
Q16
Find the odd one out with respect to GIS software.
- A. ArcGIS
- B. QGIS
- C. SAGA GIS
- D. SummitCorrect
Explanation. The book lists ArcGIS, ArcView 3.2, QGIS and SAGA GIS as GIS software. Summit is IBM's supercomputer, described in the Fact File as the world's fastest.
Q17
Consider the following statements about the functions of GIS:
1. There are two basic methods of digitization: manual digitizing and scanning.
2. Raster and Vector are the two most common types of data models.
3. Data storage is based on a Generic Data Model used to convert map data into a digital form.
4. The heart of GIS is its data capture capability.
Which of the statements given above are correct?
- A. 1 and 2 only
- B. 1, 2 and 3 onlyCorrect
- C. 2, 3 and 4 only
- D. 1, 2, 3 and 4
Explanation. Statements 1, 2 and 3 come straight from the sections on data capture and data storage. Statement 4 is wrong: the book says the heart of GIS is the analytical capability of the system.
Q18
Transit, the first satellite navigation system deployed by the US military, based its operations on
- A. the Doppler effectCorrect
- B. the quasi-zenith orbit
- C. dual frequency signals
- D. synthetic aperture radar
Explanation. Transit's operations were based on the Doppler effect: the received frequency differs slightly from the broadcast frequency because the satellite moves with respect to the receiver.
Q19
The Galileo constellation of the European Union will comprise 30 satellites in total. How are they made up?
- A. 24 operational and 6 spareCorrect
- B. 20 operational and 10 spare
- C. 28 operational and 2 spare
- D. 26 operational and 4 spare
Explanation. The Galileo constellation will have 30 satellites: 24 operational satellites plus 6 spare satellites, circulating in medium Earth orbit on three orbital planes.
Q20
Match the terms with their meanings:
a) Photogrammetry - 1) a device for receiving a radio signal and automatically transmitting a different signal
b) Transponder - 2) an integrated circuit that contains all the functions of a central processing unit
c) Microprocessor - 3) a substance toxic to plants, used to destroy unwanted vegetation
d) Herbicide - 4) the use of photography in surveying and mapping to ascertain measurements
- A. a-4, b-1, c-2, d-3Correct
- B. a-1, b-4, c-3, d-2
- C. a-4, b-2, c-1, d-3
- D. a-2, b-1, c-4, d-3
Explanation. From the glossary: photogrammetry uses photography to ascertain measurements; a transponder receives a radio signal and transmits a different one; a microprocessor holds all CPU functions; a herbicide destroys unwanted vegetation.
