UPSC Prelims 2014 · Question 67 of 100

UPSC Prelims 2014 question on Solar Photovoltaics Solar Thermal

With reference to technology for solar power production, consider the following statements:

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?

  1. 1 only
  2. 2 and 3 only
  3. 1, 2 and 3
  4. None
Show answer

Answer: A. 1 only

Verdict

The answer is 1 only. The description of photovoltaic and solar thermal technology is right, but the current type and the manufacturing base claims are both wrong.

Analysis

Statement 1 is CORRECT. Photovoltaics converts light directly into electricity, while solar thermal concentrates the sun's heat to raise steam that then drives a generator. Statement 2 is INCORRECT and reversed. Photovoltaic cells produce direct current, which an inverter converts to alternating current; solar thermal, running a conventional turbine, produces alternating current. Statement 3 is INCORRECT. India has a domestic photovoltaic manufacturing base, and the disputes over domestic content requirements under the national solar mission arose precisely because that base existed.

Source

Technical material on types of solar energy technology.

How to crack it

Statement 2 is a straight inversion, and inversions are the commonest way UPSC makes a technical statement false. Test it against mechanism: any device generating electricity chemically or photoelectrically gives direct current, and any device spinning a turbine gives alternating current. That rule covers batteries, solar cells, thermal plants and hydel plants alike. Fuse it with the news hook here, the United States dispute at the WTO over the solar mission's local content rules, which itself confirms that Indian photovoltaic manufacturing exists.

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