Previous Year Questions General Science for CDS & CAPF: 28th September


Previous year questions must be prepared when it comes to the preparation of CDS & CAPF examinations. Defenceadda is providing you with the previous year questions of General Science Section.


Q1. Which one of the following is heavy water used in nuclear reactor? 
(a) Water having molecular weight 18 u 
(b) Water having molecular weight 20 u 
(c) Water at 4°C but having molecular weight 19 u 
(d) Water below the ice in a frozen sea 

Q2. The rusting of iron nail  
(a) Decreases its weight 
(b) Increases its weight 
(c) Does not affect weight but iron is oxidized 
(d) Does not affect weight but iron is reduced 

Q3. Which one of the following when dissolved in H_2 O gives hissing sound?  
(a) Limestone 
(b) Slaked lime 
(c) Soda lime 
(d) Quicklime 

Q4. Commercial vulcanization of rubber involves  
(a) Sulphur 
(b) Carbon 
(c) Phosphorus 
(d) Selenium 

Q5. Aqua-regia used by alchemists to separate silver and gold is a mixture of  
(a) Hydrochloric acid (concentrated) and nitric acid (concentrated) 
(b) Hydrochloric acid (concentrated) and sulphuric acid (concentrated) 
(c) Nitric acid (concentrated) and sulphuric acid (concentrated) 
(d) Hydrochloric acid (dilute) and sulphuric acid (dilute)

Q6. In human body, what is the number of cervical vertebrae?  
(a) 5 
(b) 7 
(c) 8 
(d) 12

Q7. Which of the following is a rich source of energy? 
(a) Protein 
(b) Lipid 
(c) Carbohydrate 
(d) Vitamin 

Q8. By using which one of the following techniques, is DNA fingerprinting done?  
(a) ELISA 
(b) RIA 
(c) Northern Blotting 
(d) Southern Blotting 

Q9. Which chamber of human heart pumps fully oxygenated blood to aorta and then to the body? 
(a) Right auricle 
(b) Left auricle 
(c) Right ventricle 
(d) Left ventricle 

Q10. Which one of the following is a major constituent of biogas?  
(a) Carbon dioxide 
(b) Methane 
(c) Hydrogen 
(d) Nitrogen dioxide 

SOLUTIONS
S1. Ans.(b)
Sol. Heavy water (D_2 O) is used in nuclear reactor as a moderator. The deuterium is an isotope of hydrogen. Its atomic mass is 2. Hence its molecular weight is 20u(2+18). 

S2. Ans.(b)
Sol. The rusting of iron nail takes place in the presence of air (oxygen) and water (moisture). It increases the weight of iron nail due to the formation of rust. 
4Fe+3O_2+xH_2 O→2Fe_2 O_3.xH_2 O 

S3. Ans.(d)
Sol. On adding water, quicklime (CaO) gives a hissing sound and forms calcium hydroxide commonly known as slaked lime. 
CaO+H_2 O→C Ca (OH_2 )+15000 calories 

S4. Ans.(a)
Sol. Vulcanization is a process in which natural rubber is treated with 3-5% sulphur. It introduces sulphur bridges between polymer chains thereby increasing its tensile strength, elasticity and resistance to abrasion. 

S5. Ans.(a)
Sol. Aqua-regia is a mixture of concentrated nitric acid and concentrated hydrochloric acid in the ratio 1 : 3 respectively. It is a very powerful oxidizing mixture. 

S6. Ans.(b)
Sol. In vertebrates, cervical vertebrae are immediately inferior to the skull. They are smallest of true vertebrae and their number in human body is 7. 

S7. Ans.(c)
Sol. Carbohydrates is an important nutrient in human. It is a good and rich source of energy. 

S8. Ans.(d)
Sol. DNA fingerprinting includes the extraction and identification of the base pair pattern of an individual’s DNA. The identification process of specific DNA sequences is carried out by Southern blotting.

S9. Ans.(d)
Sol. The human heart possesses four chambers, two superior atria and two inferior ventricles. The atria are getting chambers and ventricles are providing chambers. Left ventricle pumps fully oxygenated blood to aorta then to the body. Right atrium gets deoxygenated blood from superior vena cava
S10. Ans.(b)
Sol. Biogas is typically a gas evolved by the biological breakdown of organic wastes in absence of O2. It is used as biofuel and made up basically of CH4 (50-75%), CO2 (25-50%) N2 (0-10%), H2 (0-1%), H2 s (0-3%) and O2 (0-1%). 

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