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General ScienceEasyAsked in: NDA · NDA-I 2021, GAT

The image we see in plane mirror is

  1. A.real and thus can be photographed.
  2. B.virtual and nearer than the object.
  3. C.virtual and is laterally inverted.
  4. D.real but cannot be photographed.

Correct answer

C. virtual and is laterally inverted.

Explanation

The correct answer is C, virtual and is laterally inverted. A plane mirror forms an image behind the mirror where light only seems to come from, with left and right swapped.

Reflected rays from a plane mirror spread out, and our eyes trace them back to a point behind the glass; no light actually reaches that point, so the image is virtual and cannot be caught on a screen. The image is upright, the same size as the object and as far behind the mirror as the object is in front. Lateral inversion is why the word AMBULANCE is painted in mirror writing on the front of ambulances.

A is wrong because the image is not real; a camera can photograph it only because its lens treats the reflected rays like any other object.

B is wrong because the image is at the same distance behind the mirror as the object is in front.

D is wrong on both counts: the image is virtual, and it can be photographed.

Exam tip: plane mirror image = virtual, erect, same size, same distance, laterally inverted.

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Q1.General ScienceAsked in: UPSC Civil Services · CSE Prelims 2019, GS Paper IMedium

Recently, there was a growing awareness in our country about the importance of Himalayan nettle (Girardinia diversifolia) because it is found to be a sustainable source of

  1. A.anti-malarial drug
  2. B.biodiesel
  3. C.pulp for paper industry
  4. D.textile fibre
Show answer
Correct answer: D. textile fibre

The Himalayan nettle yields a strong natural fibre that can be spun and woven into cloth. Girardinia diversifolia, known as Himalayan giant nettle or allo, is a stinging shrub that grows wild in the moist forests of the Himalayas, including Uttarakhand, Himachal Pradesh and the North-east, as well as Nepal.

Q2.General ScienceAsked in: UPSC Civil Services · CSE Prelims 2020, GS Paper IEasy

Which of the following statements are correct regarding the general difference between plant and animal cells ? 1. Plant cells have cellulose cell walls whilst animal cells do not. 2. Plant cells do not have plasma membrane unlike animal cells which do. 3. Mature plant cell has one large vacuole whilst animal cell has many small vacuoles. Select the correct answer using the code given below:

  1. A.1 and 2 only
  2. B.2 and 3 only
  3. C.1 and 3 only
  4. D.1,2 and 3
Show answer
Correct answer: C. 1 and 3 only

Plant cells have a cellulose wall and one large central vacuole, but they do have a plasma membrane, just like animal cells.

Q3.General ScienceAsked in: UPSC Civil Services · CSE Prelims 2017, GS Paper IEasy

Consider the following statements : 1. In tropical regions, Zika virus disease is transmitted by the same mosquito that transmits dengue. 2. Sexual transmission of Zika virus disease is possible. Which of the statements given above is/are correct ?

  1. A.1 only
  2. B.2 only
  3. C.Both 1 and 2
  4. D.Neither 1 nor 2
Show answer
Correct answer: C. Both 1 and 2

Zika is spread mainly by the Aedes mosquito that also carries dengue, and it can pass between sexual partners. The Zika virus is a flavivirus first identified in Uganda's Zika forest in 1947.

Q4.General ScienceAsked in: UPSC Civil Services · CSE Prelims 2020, GS Paper IEasy

What is the importance of using Pneumococcal Conjugate Vaccines in India ? 1. These vaccines are effective against pneumonia as well as meningitis and sepsis. 2. Dependence on antibiotics that are not effective against drug-resistant bacteria can be reduced. 3. These vaccines have no side effects and cause no allergic reactions. Select the correct answer using the code given below :

  1. A.1 only
  2. B.1 and 2 only
  3. C.3 only
  4. D.1, 2 and 3
Show answer
Correct answer: B. 1 and 2 only

The vaccine protects against several pneumococcal diseases and so cuts antibiotic use, but no vaccine is free of side effects.

Q5.General ScienceAsked in: NDA · NDA-I 2018, GATMedium

Which one of the following is NOT true for bleaching powder?

  1. A.It is used as a reducing agent in chemical industries
  2. B.It is used for bleaching wood pulp in paper factories
  3. C.It is used for disinfecting drinking water
  4. D.It is used for bleaching linen in textile industry
Show answer
Correct answer: A. It is used as a reducing agent in chemical industries

Bleaching powder is an oxidising agent, not a reducing agent, so this statement is the false one. Bleaching powder, calcium oxychloride (CaOCl₂), is made by passing chlorine gas over dry slaked lime, Ca(OH)₂.