Science Quiz for NDA, CDS & other Defence Exams-10th August


Q1. The escape velocity for a body of mass 1 kg from the Earth surface is 11.2 kms¯¹. The escape velocity for a body of mass 100 kg would be
(a) 11.2 × 10² kms¯¹
(b) 112 kms¯¹
(c) 11.2 kms¯¹
(d) 11.2 × 10¯² kms¯¹

Q2.  Which of the following acid is found in the stomach of man?
(a) Sulphuric acid
(b) Hydrochloric acid
(c) Nitric acid
(d) Picric acid

Q3. A cell has an emf 1.5 V. When connected across an external resistance of 2 Ω, the terminal potential difference falls to 1.0 V. The internal resistance of the cell is 
(a) 2Ω 
(b) 1.5 Ω
(c) 1.0 Ω
(d) 0.5 Ω

Q4. The specific resistance of a conductor increases with 
(a) Increase in temperature 
(b) Increase in cross-sectional area 
(c) Decrease in length 
(d) The decrease in cross-sectional area

Q5. There is the following relation between the velocity (v) and time (t) of a particle: 
v = 20 + 0.1 t² 
The particle is—
(a) Moving with uniform acceleration
(b) Having uniform retardation
(c) Moving with non-uniform acceleration
(d) Moving with zero acceleration


Q7. In a period, the elements are arranged in the order of- 
(a) Constant charges in the nucleus 
(b) Equal charges in the nucleus 
(c) Decreasing charges in the nucleus 
(d) Increasing charges in the nucleus 

Q8. Transition metals are often paramagnetic owing to- 
(a) High Melting point and Boiling Point
(b) The presence of vacant orbitals 
(c) The presence of unpaired electrons  
(d) Malleability and ductility 


Q10. Blood pressure is controlled by the hormone.
(a) Vasopressin
(b) Oxytocin
(c) Estrogen
(d) Testosterone

Q11.  Which one of the following is responsible for blue baby Syndrome? 
(a) Fluoride 
(b) Nitrate 
(c) Arsenic 
(d) Lead 

Q12. Which of the following is involved in controlling blood sugar level? 
(a) Pituitary gland 
(b) Islets of Langerhans 
(c) Hypothalamus 
(d) Spleen

Q13. Which of the following cause the rusting of iron? 
I. Oxidation 
II. Reduction 
III. A chemical reaction with oxygen 
IV. A chemical reaction with CO₂
Select the correct answer from the codes given below. 
(a) I and II
(b) I and III
(c) II and III
(d) III and IV

Q14. The element having the lowest melting point in the periodic table is- 
(a) Hg 
(b) He 
(c) W 
(d) Cs 

Q15. The circular motion of a particle with constant speed is 
(a) Simple harmonic but not periodic 
(b) Periodic and simple harmonic 
(c) Neither periodic nor simple harmonic 
(d) Periodic but not simple harmonic

SOLUTIONS

S1. Ans. (c)
Sol. Escape velocity is independent of the mass of projectile which is projected.

S2. Ans. (b)
Sol. Hydrochloric acid plays an important role in food digestion. The acid is made by parietal cells in the stomach lining and does its job in the stomach cavity, or lumen. Hydrochloric acid converts pepsinogen into an enzyme called pepsin.

S7. Ans. (d)
Sol. The first ionization energy generally increases ongoing across a period. This is because on crossing a period, more protons are being added to the nuclei of the atoms. This results in an increase in nuclear charge. The electrons in the outer energy levels will be more tightly held, and more difficult to remove.

S8. Ans. (c)
Sol. Transition elements containing one or more unpaired electrons show paramagnetic behavior where the effects of individual electrons are not mutually compensated. The magnetic moment due to unpaired electron spins is aligned parallel to the external magnetic field more effectively.

S9. Ans. (b)

S10. Ans. (a)
Sol. Antidiuretic hormone or vasopressin acts on renal collecting ducts via V2 receptors to increase water permeability which leads to decreased urine formation.T his increases blood volume, cardiac output, and arterial pressure.

S11. Ans. (b) 
Sol. Nitrates in drinking water. A sort of "blue baby syndrome" can also be caused by methemoglobinemia. It is widely believed to be caused by nitrate contamination in groundwater resulting in decreased oxygen carrying capacity of hemoglobin in babies leading to death.

S12. Ans. (b)
Sol. The islets of Langerhans are responsible for the endocrine function of the pancreas. The inability of the islet cells to make insulin or the failure to produce amounts sufficient to control blood glucose level is the causes of diabetes mellitus. They are named for the German physician Paul Langerhans, who first described them in 1869. The normal human pancreas contains about 1,000,000 islets.

S13. Ans. (b)
Sol. Corrosion is defined as the chemical or electrochemical degradation of metals due to their reaction with the environment. The corrosion of iron, better known as rusting, is an oxidation-reduction process that destroys iron objects left out in open, moist air.

S14. Ans. (b)
Sol. Helium (He) is a colorless, odorless, tasteless, non-toxic, inert monatomic chemical element that heads the noble gas series in the periodic table and whose atomic number is 2. It’s boiling and melting points are the lowest among the elements and it exists only as a gas except in extreme conditions.

S15. Ans. (d)
Sol. In a circular motion, particle repeats its motion after equal intervals of time. So, the particle moving on a circular path is periodic but not simple harmonic as it does not execute to and fro motion about a fixed point.

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