UPSC Prelims 2013 · GS Paper I
Question 29: Environment and Ecology
Due to improper/indiscriminate disposal of old and used computers or their parts, which of the following are released into the environment as e-waste?
- 1.Beryllium
- 2.Cadmium
- 3.Chromium
- 4.Heptachlor
- 5.Mercury
- 6.Lead
- 7.Plutonium
Select the correct answer using the codes given below.
AnswerUPSC’s answer is (b).
Old computers contain toxic metals: beryllium (in connectors and motherboards), cadmium (in batteries and chips), chromium (in metal casings), mercury (in switches and screens) and lead (in solder and CRT glass). Heptachlor is an organochlorine pesticide and plutonium is a radioactive fuel; neither is used in computers. So the correct set is 1, 2, 3, 5 and 6.
- 1. Beryllium is used in connectors and motherboards.
- 2. Cadmium is in batteries, chips and semiconductors.
- 3. Chromium is used for metal casings and corrosion protection.
- 4. Heptachlor is a pesticide, not a computer component.
- 5. Mercury is in switches and flat-screen lamps.
- 6. Lead is in solder and CRT glass.
- 7. Plutonium is a nuclear fuel, not a computer component.
How you could have got this
- If you were sure statement 4 is not correct, (a), (c) and (d) go: each of them includes 4.
What you needed to know: Heptachlor is a pesticide, not a computer component.
Only (b) is left. You didn’t need statements 1, 2, 3, 5, 6 or 7.
Which options go is worked out from UPSC’s key and the options, not by a model.
Why each option is right or wrong
- (a) Wrong. It includes heptachlor and plutonium, and leaves out cadmium and mercury.
- (b) Correct. Beryllium, cadmium, chromium, mercury and lead.
- (c) Wrong. It includes heptachlor and plutonium and leaves out lead, beryllium and chromium.
- (d) Wrong. Heptachlor and plutonium are not found in computers.
Answer: UPSC’s key. Explanation: written by UPSC Grade, not by UPSC.
Source: UPSC, Civil Services (Preliminary) Examination 2013, General Studies Paper I, Series A. The paper on upsc.gov.in.