UPSC  Physics

111. Graphene is frequently in news recently. What is its importance?
1. It is a two-dimensional material and has good electrical conductivity.
2. It is one of the thinnest but strongest materials tested so far.
3. It is entirely made of silicon and has high optical transparency.
4. It can be used as ‘conducting electrodes’ required for touch screens, LCDs and organic LEDs.
Which of the statements given above are correct?

1 and 2 only 3 and 4 only 1, 2 and 4 only 1, 2, 3 and 4

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112. electrically charged particles from space travelling at speeds of several hundred km/sec can severely harm living beings if they reach the surface of the Earth. What prevents them from reaching the surface of the Earth?

The Earth’s magnetic field diverts them towards its poles Ozone layer around the Earth reflects them back to outer space Moisture in the upper layers of atmosphere prevents them from reaching the surface of the Earth None of the statements (a), (b) and (c) given above is correct

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113. The known forces of nature can be divided into four classes, viz., gravity, electromagnetism, weak nuclear force and strong nuclear force. With reference to them, which one of the following statements is not correct?

Gravity is the strongest of the four Electromagnetism acts only on particles with an electric charge Weak nuclear force causes radioactivity Strong nuclear force holds protons and neutrons inside the nucleus of an atom

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114. With reference to SOLAR IMPULSE 2(Si2) statements:
1. Swiss explorers Bertrand Piccard and André Borschberg are the founders, pilots and driving force behind Solar Impulse, the first airplane of perpetual endurance, able to fly day and night without a drop of fuel.
2.The Round-The-World flight started from Abu Dhabi, on March 9. The route includes stop-overs in Oman, India, Myanmar and China. After trying to cross the Pacific Ocean via Hawaii, Si2 should fly across the U.S.A. and over the Atlantic Ocean, heading back to Abu Dhabi.
3. Si2 had arrived in Ahmedabad on March 10 after covering a distance of 1465 km from Muscat — it’s first stop in India and second in its global tour. In India it took off from the city of Indore for Myanmar.
Which of the statements given above is/are correct?

1 and 3only 1 and 2 only 2 and 3 only 1, 2 and 3

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115. Which of the following physical phenomena are responsible for the formation of Rainbow when sunlight falls on drops of rain?

Refraction Dispersion Internal Reflection All of the Above

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116. With reference to Sound waves consider the following statements:
1. Human ear is capable of detecting sound waves ranging between approximately 20 Hz to 20 000 Hz.
2. Sound waves in air are Transverse waves, where displacement of the medium is parallel to the propagation of the wave.
3. Sound generally travels faster in gases and liquids than in Solid.
Which of the statements given above is/are correct?

1 only 1 and 2 only 2 and 3 only 1, 2 and 3

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117. For reproducing sound, a CD (Compact Disc) audio player uses a:

quartz crystal titanium needle laser beam barium titanate ceramic

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118. Which one of the following does a TV remote control unit use to operate a TV set?

Light waves Sound waves Microwaves Radio waves

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