Daily Static MCQs Quiz for UPSC, IAS, UPPSC/UPPCS, MPPSC. BPSC, RPSC & All State PSC Exams
Subject : Science and Technology
1. Consider the following statements:
1.X-ray fluorescence is commonly used to study the composition of materials in a non-destructive manner.
2. When the sun gives out solar flares, a large amount of X-ray radiation falls on the moon, triggering X-ray fluorescence.
Which of the above statements is/are correct?
(a) 1 only
(b) 2 only
(c) Both 1 and 2
(d) Neither 1 nor 2
Answer: (C)
Explanation: Scientists from Indian Space Research Organisation (ISRO) have mapped out the global distribution of sodium on the Moon’s surface. They used the CLASS instrument (Chandrayaan-2 large area soft X-ray spectrometer) carried by Chandrayaan-2. This is the first effort to provide a global-scale measurement of sodium on the lunar surface using X-ray fluorescent spectra. X-ray fluorescence is commonly used to study the composition of materials in a non-destructive manner. When the sun gives out solar flares, a large amount of X-ray radiation falls on the moon, triggering X-ray fluorescence. Hence, both statements are correct.
2. Consider the following statements regarding Hydrogen:
1. Hydrogen is the lightest and first element on the periodic table.
2. Water is the most abundant compound of hydrogen found on earth.
3. Because of its highly combustible property, Hydrogen as a fuel can be used only in internal combustion engines and not in spacecraft propulsion.
How many of the above statements is/are correct?
(a) Only one
(b) Only two
(c) All three
(d) None
Answer: (B)
Explanation: Hydrogen is the lightest and first element on the periodic table. Since the weight of hydrogen is less than air, it rises in the atmosphere and is therefore rarely found in its pure form, H2. Hydrogen fuel is a zero-emission fuel burned with oxygen. It can be used in fuel cells or internal combustion engines. It is also used as a fuel for spacecraft propulsion. It is the most abundant element in the universe. The sun and other stars are composed largely of hydrogen. Astronomers estimate that 90% of the atoms in the universe are hydrogen atoms. Hydrogen is a component of more compounds than any other element. Water is the most abundant compound of hydrogen found on earth. Hence, statement 3 is not correct.
3. Consider the following statements regarding Air-independent propulsion:
1. It is a technology which allows a non-nuclear submarine to operate by using the atmospheric oxygen.
2. It is based on the combustion of oxygen and ethanol to augment battery-powered propulsion.
3. The Non-nuclear submarines running on Air-independent propulsion can be virtually silent.
Which of the above statements is/are correct?
(a) 1 and 2 only
(b) 2 and 3 only
(c) 1 and 3 only
(d) 1, 2 and 3
Answer: (B)
Explanation: It is a technology which allows a non-nuclear submarine to operate without the need to access atmospheric oxygen (by surfacing or using a snorkel). It can augment or replace the diesel-electric propulsion system of non-nuclear vessels. It is based on the combustion of stored oxygen and ethanol to augment battery-powered propulsion. AIP significantly improves stealth because it enables a submarine to generate electricity for services and battery charging and propulsion while completely submerged. AIP systems also generate electricity, powering a submarine to operate and also generate oxygen, lighting and amenities for crew. The Non-nuclear submarines running on battery power or AIP can be virtually silent. Hence, statement 1 is not correct.
4. Consider the following statements regarding Nuclear Fusion:
1. Nuclear Fusion reaction is possible at the kind of temperature that exists at the core of the Sun and the stars.
2. The fusion reaction produces almost no carbon emissions and produces much less radioactive waste compared to fission.
3. The only disadvantage for fusion reaction is that the raw materials are not sufficiently available.
How many of the above statements is/are not correct?
(a) Only one
(b) Only two
(c) All three
(d) None
Answer: (A)
Explanation: Nuclear Fusion is possible at very high temperatures, of the order of a few hundred million degrees Celsius, the kind of temperature that exists at the core of the Sun and the stars. Recreating such extreme temperatures is no easy task. The materials that will make up the reactor, too, need to be able to withstand such huge amounts of heat. There are several other complications. At such high temperatures, matter exists only in the plasma state, where atoms break up into positive and negative ions due to excessive heat. Plasma, which has a tendency to expand very fast, is extremely difficult to handle and work with. But the benefits of fusion reaction are immense. Apart from generating much more energy, fusion produces no carbon emissions, the raw materials are in sufficient supply, produces much less radioactive waste compared to fission, and is considered much safer. Hence, statement 3 is not correct.
5.In order to stay over the same location on the Earth, a geostationary satellite must be directly above the:
(a) Tropic of Cancer
(b) Either North or South Pole
(c) Equator
(d) Tropic of Capricorn
Answer: (C)
Explanation: Most of the communication satellites today are placed in a geostationary orbit. Geostationary satellites in orbits circle the Earth at the same rate as the Earth spins. The Earth takes nearly 24 hours to make one full revolution around the earth allowing them to observe a location constantly on earth since earth too rotates at the same speed. So based on Kepler’s Laws of Planetary Motion, this would put the satellite at approximately 35,790 km above the Earth. The satellites are located near the equator since at this latitude there is a constant force of gravity from all directions. At other latitudes, the bulge at the centre of the Earth would pull the satellite down. Hence, option (c) is correct.
