Science and Technology (Part-I)

Total Questions: 50

11. Consider the following statements: [2010]

The satellite Oceansat-2 launched by India helps in

1. estimating the water vapour content in the atmosphere.

2. predicting the onset of monsoons.

3. monitoring the pollution of coastal waters.

Which of the statements given above is/are correct?

Correct Answer: (d) 1, 2 and 3
Solution:Oceansat-2 continues with the service of oceansat-1. The main objectives of oceansat-2 are to study surface winds and ocean surface strata, observation of chlorophyll concentration, monitoring of phytoplanktion blooms, study of atmospheric aerosol and suspended sediments in wath.
Oceansat-2 satellite mainframe systems derive their heritage from previous IRS missions and launched by PSLV-C14 from Satish Dhawan Space Centre, Sriharikota on Sept. 23, 2009.
It carries three payloads:
• Ocean Colour Monitor (OCM)
• Ku-band Pencil Beam scatterometer (SCAT) developed by ISRO
• Radio Occultation Sounder for Atmosphere (ROSA) developed by the Italian Space Agency.

12. With reference to technologies for solar power production, consider the following statements: [2014-1]

1. 'Photovoltaics' is a technology that generates electricity by direct conversion of light into electricity, while 'Solar Thermal' is a technology that utilizes the Sun's rays to generate heat which is further used in electricity generation process.

2. Photovoltaics generates Alternating Current (AC), while Solar Thermal generates Direct Current (DC).

3. India has manufacturing base for Solar Thermal technology, but not for Photovoltaics.

Which of the statements given above is/are correct?

Correct Answer: (a) 1 only
Solution:Photovoltaics' is a technology that generates electricity by direct conversion of light into electricity, while 'Solar Thermal' is a technology that utilizes the Sun's rays to generate heat which is further used in electricity generation process. Both Photovoltaic cells and solar thermal generate direct current (DC). India has a manufacturing base for both.
Photovoltaic (Solar) Cells – Working
• Photovoltaic cells are made up of two or more layers of semiconductors, one of which is positive and the other is negative, lined up next to each other.
• Sunlight, which is made up of small energy packets known as photons, strikes the cell and is either reflected, transmitted, or absorbed.
• When photons are absorbed by the photovoltaic cell’s negative layer, their energy is converted to an electron in one of the cell’s atoms.
• The electron departs the atom’s outer shell as its energy increases. The released electron naturally migrates to the positive layer, resulting in a potential difference between the two layers.
• The electron flows through the circuit when the two layers are coupled to an external circuit, providing a current.

13. Which of the following pairs is/are correctly matched? [2014-1]

1. Cassini-Huygens : Orbiting the Venus and transmitting data to the Earth

2. Messenger : Mapping and investigating the Mercury

3. Voyager 1 and 2 : Exploring the outer solar system

Select the correct answer using the code given below.

Correct Answer: (b) 2 and 3 only
Solution:Cassini--Huygens is an unmanned spacecraft sent to the planet Saturn. Therefore, option 1 is wrong, this eliminates option (a), (c) and (d). Now we are left with final answer B only 2 and 3. MESSENGER is a robotic NASA spacecraft orbiting the planet Mercury. Voyager 1 (September 1977) and voyager 2 (Aug 1977) were launched to study the outer Solar System.

14. With reference to 'Astrosat', the astronomical observatory launched by India, which of the following statements is/are correct? [2016-1]

1. Other than USA and Russia, India is the only country to have launched a similar observatory into space.

2. Astrosat is a 2000 kg satellite placed in an orbit at 1650 km above the surface of the Earth.

Select the correct answer using the code given below.

Correct Answer: (d) Neither 1 nor 2
Solution:(i) India has become only the fifth country after the US, Russia, Europian Union and Japan, to have an eye scanning the exotic depths of the universe after the ASTROSAT, the Indian Space Research Organisation's multi-wavelength space observatory, was successfully placed in orbit.

(ii) Astrosat weighs 1513 kgs. Hence 2nd statement also wrong.

15. Consider the following statements: [2016-1]

The Mangalyaan launched by ISRO :

1. is also called the Mars Orbiter Mission.

2. made India the second country to have a spacecraft orbit the Mars after USA.

3. made India the only country to be successful in making its spacecraft orbit the Mars in its very first attempt.

Which of the statements given above is/are correct?

Correct Answer: (c) 1 and 3 only
Solution:(i) The Mars Orbiter Mission (MOM), also called Mangalyaan. It is India's first interplanetary mission and ISRO has become the fourth space agency to reach Mars, after the Soviet space program, NASA, and the European Space Agency. It is the first Asian nation to reach Mars orbit, and the first nation in the world to do so in its first attempt.

(ii) Statement 1 and 3 are right. Apart from India and USA, Russia and European space agency also have it. European Space Agency's Mars Express has two components 1) Mars Orbiter 2) Beagle 2 Lander. Hence 2nd statement is wrong. Hence by elimination we are left with choice (c).

16. 'Project Loon', sometimes seen in the news, is related to : [2016-1]

Correct Answer: (b) wireless communication technology
Solution:(i) Project loon is a network of balloons travelling on the edge of space, designed to extend internet connectivity to people in rural & remote areas worldwide.
(ii) Under Project Loon, Google Inc. aims to provide internet connectivity via using helium balloons. Hence (b) is the apt choice.
• Whitespace Internet: It uses a part of the radio spectrum known as White spaces. White Space refers to the unused broadcasting frequencies in the wireless spectrum. These spaces can provide broadband internet access that is similar to that of 4G mobile. Microsoft is providing whitespace internet to underserved areas of several countries.
• Starlink: It is a satellite internet constellation being constructed by SpaceX with the aim to bring internet access to rural and underserved areas around the world.

17. The terms 'Event Horizon', 'Singularity', 'String Theory' and 'Standard Model' are sometimes seen in the news in the context of : [2016-1]

Correct Answer: (a) Observation and understanding of the Universe
Solution:Nature is governed by four fundamental forces electromagnetic, strong, weak and gravitational. Standard Model explains the first three forces. Event horizon is the imaginary boundary surrounding the black hole from beyond which light cannot escape and The singularity constitutes the centre of a black hole and is hidden by the object's "surface".

18. With reference to the Indian Regional Navigation Satellite System (IRNSS), consider the following statements : [2018-1]

1. IRNSS has three satellites in geostationary and four satellites in geosynchronous orbits.

2. IRNSS covers entire India and about 5500 sq. km beyond its borders.

3. India will have its own satellite navigation system with full global coverage by the middle of 2019.

Which of the statements given above is/are correct?

Correct Answer: (a) 1 only
Solution:In IRNSS, Out of the seven satellites of space segment; four satellites are in geosynchronous orbit and three satellites are in geostationary orbit. So 1st statement is right. "D" is eliminate(d) [And we no longer need to worry about the validity of statement #3, because there is no option where 1 and 3 are together].

IRNSS covers an area of about 1,500 km around Indi(a) So, 2nd statement is wrong. B and C are eliminate (d). Therefore, Answer has to be a '1' only.

19. With reference to India's satellite launch vehicles, consider the following statements: [2018-1]

1. PSLVs launch the satellites useful for Earth resources monitoring whereas GSLVs are designed mainly to launch communication satellites.

2. Satellites launched by PSLV appear to remain permanently fixed in the same position in the sky, as viewed from a particular location on Earth.

3. GSLV Mk III is a four-staged launch I vehicle with the first and third stages 1 using solid rocket motors; and the second and fourth stages using liquid rocket engines.

Which of the statements given above is/are correct.?

Correct Answer: (a) 1 only
Solution:ISRO developed PSLV to launch satellites into polar orbits and GSLV to launch geosynchronous satellites into geostationary orbits. Geostationary satellites orbit around the earth in 24 hours and since the earth rotates with the same period, the satellite would appear fixed from any point on earth. So, statement#2 is wrong.

GSLV is a 3-stage launch vehicle, where first 2 stages are similar to PSLV with same solid and liquid nature of fuel but the third stage is completely different, i.e., cryogenic stage. So third statement is WRONG. By elimination, we're left with answer A: only 1.

20. For the measurement/estimation of which of the following are satellite images/remote sensing data used? [2019-1]

1. Chlorophyll content in the vegetation of a specific location

2. Greenhouse gas emissions from rice paddies of a specific location

3. Land surface temperatures of a specific location

Select the correct answer using the code given below:

Correct Answer: (d) 1, 2 and 3
Solution:Satellite images/remote sensing data can be used to measure/estimate chlorophyll content in vegetation, greenhouse gas emissions from rice paddies, and land surface temperatures of specific locations.
Satellite Remote Sensing Applications
ApplicationRemote Sensing Principle UsedWhat is Measured/Estimated?
Chlorophyll Content (Vegetation Health)Reflectance in Visible (Red) and Near-Infrared spectrumVegetation Indices (e.g., NDVI) indicating chlorophyll levels
Greenhouse Gas Emissions (e.g., Methane from Rice Paddies)Spectral absorption/emission signatures of gasesConcentration or flux of specific gases
Land Surface TemperaturesThermal infrared radiation emitted by the surfaceTemperature of the Earth's land surface