UPSC Prelims 2014 · GS Paper I
Question 7: Science and Technology
With reference to technologies 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?
AnswerUPSC’s answer is (a).
Photovoltaic cells convert sunlight directly into electricity, while solar thermal technology uses the Sun's rays to produce heat, which makes steam to run a turbine. Photovoltaic cells produce direct current, which an inverter converts to alternating current; a solar thermal plant's turbine and generator produce alternating current. India has manufacturers of both photovoltaic cells and modules and solar thermal equipment. So only statement 1 is correct.
- 1. Photovoltaics convert light directly; solar thermal makes heat first, then electricity.
- 2. Photovoltaics give direct current; solar thermal turbines give alternating current.
- 3. India also has a photovoltaic manufacturing base.
Why each option is right or wrong
- (a) Right. Only statement 1 correctly describes the two technologies.
- (b) Wrong. Both statements 2 and 3 are false, as the current types are reversed and India makes photovoltaics.
- (c) Wrong. Statements 2 and 3 are false.
- (d) Wrong. Statement 1 is correct, so it is not true that none is correct.
Answer: UPSC’s key. Explanation: written by UPSC Grade, not by UPSC.
Source: UPSC, Civil Services (Preliminary) Examination 2014, General Studies Paper I, Series A. The paper on upsc.gov.in.