UPSC Prelims Practice Questions — Aditya-L1 mission offers new insights into the direction of solar eruptions

Q1. With reference to the Sun–Earth Lagrange points, consider the following statements: Which of the statements given above is/are correct?

  1. At a Lagrange point, the combined gravitational pull of the Sun and Earth supplies exactly the centripetal force a small body needs to move in step with them.
  2. Because the forces balance exactly at L1, a spacecraft placed there remains in position indefinitely without any orbit-correction manoeuvres.
  3. Since L1 is closer to the Sun than Earth is, a spacecraft at L1 completes one revolution around the Sun in less time than Earth does.
  • A. 2 and 3 only
  • B. 1 only
  • C. 1 and 2 only
  • D. 1, 2 and 3

Q2. Aditya-L1 observes the Sun from Sun–Earth L1, while the James Webb Space Telescope, an infrared observatory, operates around Sun–Earth L2. Which one of the following is a property of L2 that suits such a telescope and that L1 does not offer?

  • A. The point is gravitationally stable, so the telescope needs no station-keeping manoeuvres
  • B. The spacecraft keeps an uninterrupted view of the Sun, never occulted by Earth or the Moon
  • C. The point lies much closer to Earth than L1 does, which eases high-rate data transmission
  • D. The Sun, Earth and Moon all stay on one side, so one shield can block their light and heat

Q3. Consider the following statements: Which of the following is correct in respect of the above statements?

  1. A spacecraft in a halo orbit around Sun–Earth L1 can watch the Sun continuously, without interruption by eclipses or occultation.
  2. Sun–Earth L1 lies on the far side of Earth from the Sun, so Earth's shadow never falls on a spacecraft placed there.
  • A. Both Statement-I and Statement-II are correct and Statement-II explains Statement-I
  • B. Both Statement-I and Statement-II are correct, but Statement-II does not explain Statement-I
  • C. Statement-I is correct, but Statement-II is incorrect
  • D. Statement-I is incorrect, but Statement-II is correct

Q4. With reference to coronal mass ejections (CMEs), consider the following statements: Which of the statements given above is/are correct?

  1. A CME is an eruption of plasma, carrying magnetic field with it, from the Sun's corona into space.
  2. CMEs are launched only along the Sun–Earth line, which is why every major CME eventually reaches Earth.
  3. An Earth-directed CME can be registered by in-situ plasma instruments at Sun–Earth L1 before it reaches Earth.
  • A. 1 and 3 only
  • B. 1, 2 and 3
  • C. 1 only
  • D. 2 and 3 only

Q5. With reference to Doppler velocity imaging of the solar corona, as recently done with Aditya-L1 data, consider the following statements: Which of the statements given above is/are correct?

  1. The Doppler shift of a coronal emission line reveals how fast plasma moves across the plane of the sky as seen from the spacecraft.
  2. A Doppler velocity map can show different parts of the same coronal structure moving towards and away from the observer at the same time.
  3. Producing such maps requires spectroscopic observation of coronal emission lines, not merely images of coronal brightness.
  • A. 1 and 2 only
  • B. 1 only
  • C. 2 and 3 only
  • D. 1, 2 and 3

Q6. With reference to the scientific payloads of Aditya-L1, consider the following statements: Which of the statements given above is/are correct?

  1. The Visible Emission Line Coronagraph is an in-situ payload, because it studies the Sun's own outer atmosphere.
  2. An in-situ payload at L1 measures particles and magnetic fields at the spacecraft's own location, not at the Sun.
  3. In-situ payloads at L1 can directly sample the solar wind because L1 lies within Earth's magnetosphere, which concentrates the incoming particles.
  • A. 2 and 3 only
  • B. 2 only
  • C. 1 and 2 only
  • D. 1 and 3 only

Q7. Consider the following observations from Aditya-L1: Aditya-L1's coronagraph records Doppler-shifted coronal emission from plasma erupting in a CME close to the Sun. A few days later, an in-situ plasma analyser on the same spacecraft at L1 registers a sharp jump in solar-wind speed and density that scientists attribute to the same CME. Which of the following inferences can be drawn from the above?

  1. Combining the two kinds of observation lets scientists link an eruption at the Sun with the conditions it later produces in interplanetary space.
  2. The CME was travelling at least partly along the Sun–Earth line, in the direction of L1.
  3. The CME will necessarily produce a severe geomagnetic storm and damage power grids on Earth.
  • A. 1, 2 and 3
  • B. 1 only
  • C. 2 and 3 only
  • D. 1 and 2 only