Science Quiz for NDA, CDS & other Defence Exams

Q1. Hemoglobin is an important component of
(a) RBC
(b) WBC
(c) Platelets
(d) Cytoplasm

Q2.  Total internal reflection can occur when light tends to pass from 
(a) A denser to a rarer medium
(b) A rarer to a denser medium
(c) One medium to another of equal refractive index
(d) None of these

Q3. The refractive index of a piece of transparent quartz is the greatest for 
(a) Red light
(b) Yellow light
(c) Greenlight
(d) Violet light

Q4. Which of the following gland is both exocrine and endocrine gland?
(a) Pancreas
(b) Liver
(c) Pituitary
(d) Thyroid

Q5. Permanent hardness of water is due to the presence of 
(a) Sulphate of sodium and potassium
(b) Sulphate of magnesium and calcium
(c) Carbonates of sodium and magnesium
(d) Bicarbonates of magnesium and calcium

Q8.  A and B are two vectors and θ is the angle between them. If |A×B|=√3 (A∙B),  then the value of θ is 
(a) 60°
(b) 45°
(c) 30°
(d) 90°

Q9. The speed of sound in air is unaffected by the change in
(a) Pressure
(b) Humidity
(c) Temperature
(d) Volume

Q11. Where is the national institute of nutrition located? 
(a) Bengaluru
(b) Hyderabad 
(c) Mysore 
(d) Pune

Q12. Vitamin E is important for —
(a) Development to teeth 
(b) For the metabolism of carbohydrate 
(c) For the normal function of the reproductive system 
(d) For the normal health of epithelial membrane

Q13. Blue litmus paper is converted into red in the solution of —
(a) Acid
(b) Base
(c) Alkali 
(d) Salt

Q14. A bond formed by sharing of electrons between atoms of the elements is called- 
(a) Ionic bond 
(b) Covalent bond 
(c) Co-ordinate bond  
(d) None

Q15. H2O is liquid and H2S is a gas because–
(a) Oxygen forms stronger hydrogen bond than sulphur 
(b) Oxygen is less electronegative than sulphur 
(c) The atomic radius of oxygen is less than that of sulphur 
(d) The atomic radius of oxygen is greater than that of sulphur 
S1. Ans. (a)
Sol. Hemoglobin is present in red blood cells and is an essential chemical which carries oxygen from the lungs to other parts of the body.

S2. Ans. (a)
Sol. Total internal reflection complete reflection of a ray of light within a medium such as water or glass, denser to rare medium and surrounding surfaces back into the medium. The phenomenon occurs if the angle of incidence is greater than a certain limiting angle, called the critical angle.

S3. Ans. (d)
Sol. Violet has the greatest refractive index of a piece of transparent quartz.  n=1.52136.

S4. Ans. (a)
Sol. Functioning as an exocrine gland, the pancreas excretes enzymes to break down the proteins, lipids, carbohydrates, and nucleic acids in food. Functioning as an endocrine gland, the pancreas secretes the hormones insulin and glucagon to control blood sugar levels throughout the day.

S5. Ans. (b)
Sol. Permanent hardness in water is hardness due to the presence of the chlorides, nitrates, and sulphates of calcium and magnesium, which will not be precipitated by boiling.

S8. Ans. (a)
Sol. Given |A×B|=√3 (A∙B)  
⇒ABsin θ=√3 ABcos θ  
⇒  tan⁡θ=√3
∴ θ = 60°

S9. Ans. (a)
Sol. The speed of sound increases with the increase of temperature of the medium. The speed of sound is more in humid air than in dry air because the density of humid air is less than the density of dry air. But the speed of sound in air is unaffected by the change in pressure i.e., the speed of sound remains unchanged by the increase or decrease of pressure.

S10. Ans. (b)

S11. Ans. (b) 
Sol. The National Institute of Nutrition (NIN) is an Indian Public health, Biotechnology and Translational research center located in Hyderabad, India The institute is one of the oldest research centers in India, and the largest center, under the Indian Council of Medical Research located in the vicinity of Osmania University.

S12. Ans. (c)
Sol. Vitamin E is known as an important antioxidant to protect the reproductive system. 

S13. Ans. (a)
Sol. Blue litmus paper is used to test an acid. When a blue litmus paper immersed in an acid, the litmus paper turns red from blue indicating acid. Acids are ions that break to H+ in water. The greater the number of H+ ions, the stronger is the acid.

S14. Ans. (b)
Sol. A covalent bond, also called a molecular bond, is a chemical bond that involves the sharing of electron pairs between atoms.

S15. Ans. (a)
Sol. Water exists as a liquid at room temperature with a high boiling point. Sulphur is less electronegative than oxygen, and the S-H bond is much less polar than the O-H bond. Hence, there is no hydrogen bonding in hydrogen sulphide, and it exists as a gas normally with discrete H2S molecules.

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