[Solution] – Friday Science Quiz #4

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[Solutions]

Q.1) Consider the following statements.
1. Ability of the lens to converge or diverge light rays depend upon its focal length.
2. A concave lens of very short focal length causes less divergence than a very long focal length concave lens.

Select the correct statement using the codes given below.
a) 1 only
b) 2 only
c) Both 1 and 2
d) None of the above

Explanation- Statement 1 is obvious fact and correct.
Statement 2 is wrong. A concave lens of very short focal length causes more divergence than a very long focal length concave lens by diverging light rays away from the optical centre.

Q.2) Arrange the following in decreasing order of refractive indexes.
1. Water
2. Air
3. Ice

Select the correct answer using the codes given below.
a) 3 >1 > 2
b) 1 > 3 >2
c) 3 > 2 > 1
d) 1 > 2 > 3

Explanation– Water refractive index is 1.33, of ice is  1.31 and air is 1.

Q.3) Convex mirrors are used commonly for rare view mirror. This is because:
1. It gives inverted and diminished image.
2. It has a wider field of view as they are curved inwards.

Select the correct answer using the codes given below.
a) 1 only
b) 2 only
c) Both 1 and 2
d) None of the above

Explanation- Convex mirrors are commonly used as rear-view mirrors in vehicles. Convex mirrors are preferred because they always give an erect, though diminished, image. Also, they have a wider field of view as they are curved outwards. Thus, convex mirrors enable the driver to view much larger area than would be possible with a plane mirror.

Q.4) Which of the following are applications of Raman effect:
1. Monitoring of chemical purity in petro chemical industry
2. Identification of cancer
3. Study of gravity in black holes
4. Detection of Narcotics

Select the correct answer using the codes given below.
a) 2, 3 and 4 only
b) 1, 2 and 3 only
c) 1, 2 and 4 only
d) 1, 2, 3 and 4

Explanation- Raman effect is one of the few technique which can provide key information, easily and quickly, detailing the chemical composition and the structure of the investigated materials.
Statement 3 is not the application of Raman effect. All other are common application of Raman effect.

Q.5) Consider the following statements about smart grid project.
1. It is the project of Union Ministry of water resources for solving water shortage.
2. Ranchi is selected as a first place to have smart grid system.

Select the incorrect statement using the codes given below.
a) 1 only
b) 2 only
c) Both 1 and 2
d) None of the above

Explanation– Smart grid is the project of New Delhi Municipal Council.

Q.6) Consider the following statements regarding the human eye.
1. Light enters the eye through a thin membrane known as pupil
2. Iris controls the size of the cornea
3. Eye lens always forms real and erect image on the retina.

Which of the above statements are true in the respect of anatomical structure of human eye?
a) 1 and 2 only
b) 1,  2 and 3
c) None of the above
d) 3 only

Explanation- Light enters the eye through a thin membrane known as Cornea. Iris controls the size of pupil. The eye lens always forms an inverted real image of the object on the retina. Hence all statements are wrong.

Q.7) Consider the following statements regarding eye donation:
1. Eye donors can belong to only some specific age bracket as per as WHO convention
2. People who use spectacles, or operated with cataract, who are diabetic, or have hypertension and who are asthma patients can not donate their eyes.
3. People infected with rabies and cholera can donate their eyes.

Select the correct statement using the codes given below.
a) 1 only
b) 2 and 3 only
c) 1, 2 and 3
d) None of the above

Explanation- Some basic facts about eye donation:

1. Eye donors can belong to any age group or sex. People who use spectacles, or those operated for cataract, can still donate the eyes.
2. People who are diabetic, have hypertension, asthma patients and those without communicable diseases can also donate eyes.
3. Eyes must be removed within 4-6 hours after death.
4. ?Eye removal takes only 10-15 minutes. It is a simple process and does not lead to any disfigurement.
5.  Persons who were infected with or died because of AIDS, Hepatitis B or C, rabies, acute leukaemia, tetanus, cholera, meningitis or encephalitis cannot donate eyes.