UPSC conduct the NDA (National Defence Academy) II Exam – 2019. NDA II 2019 Paper held on 17 November 2019. This paper is Part B (General Aptitude Test). NDA (II) 2019 Part – B (General Aptitude Test) Answer Key available here.
Exam – NDA (II) 2019
Organized by – UPSC
Part – B (General Aptitude Test)
Date of Exam – 17th November, 2019
UPSC NDA (II) 2019 Exam Paper (Answer Key)
Part – B (General Aptitude Test)
51. A thin disc and a thin ring, both have mass M and radius R. Both rotate about axes through their center of mass and are perpendicular to their surfaces at the same angular velocity. Which of the following is true ?
(a) The ring has higher kinetic energy
(b) The disc has higher kinetic energy
(c) The ring and the disc have the same kinetic energy
(d) Kinetic energies of both the bodies are zero since they are not in linear motion
52. Let there be an object having some chemicals in it. It starts moving with a uniform velocity v and a chemical reaction starts happening. In this case, which of the following statement/s is/are correct?
1. Chemical reactions happening in the system cannot change the velocity of the center of mass of the object.
2. Chemical reactions happening in the system cannot change kinetic energy of the particles inside with respect to the center of mass of object.
Select the correct answer using the code given below :
(a) 1 only
(b) 2 only
(c) Both 1 and 2
(d) Neither 1 nor 2
53. In which of the following phenomena do heat waves travel along a straight line with the speed of light?
(a) Thermal conduction
(b) Thermal convection
(c) Thermal radiation
(d) Both, thermal conduction and radiation
54. Which one of the following statements regarding Ohm’s law is not correct?
(a) Ohm’s law is an assumption that current through a conductor is always directly proportional to the potential difference applied to it.
(b) A conducting device obeys Ohm’s law when the resistance of a device is independent of magnitude and polarity of applied potential difference.
(c) A conducting material obeys Ohm’s law when the resistance of material is independent of the magnitude and direction of applied electric field.
(d) All homogeneous materials obey Ohm’s law irrespective of whether the field is within range or strong.
55. When a ball bounces off the ground, which of the following changes suddenly ? (Assume no loss of energy to the floor)
(a) Its speed
(b) Its momentum
(c) Its kinetic energy
(d) Its potential energy
56. Which one of the following compounds does not exhibit a different oxidation number of the same element ?
57. Which one of the following statements about glass is not correct?
(a) Glass is often said to be a supercooled liquid.
(b) Glass has no definite melting point.
(c) Soda glass is harder than pyrex glass.
(d) Boron is present in pyrex glass.
58. Which one of the following statements is correct?
(a) Both boiling and evaporation are surface phenomena.
(b) Boiling is a surface phenomenon, but evaporation is a bulk phenomenon.
(c) Both boiling and evaporation are bulk phenomena.
(d) Boiling is a bulk phenomenon, but evaporation is a surface phenomenon.
59. Which one of the following statements about diamond and graphite is not correct?
(a) Diamond has a tetrahedral structure, whereas graphite has a hexagonal planar structure.
(b) Both physical and chemical properties of diamond and graphite are different.
(c) Graphite is soft but diamond is hard.
(d) Graphite is a good conductor of electricity while diamond is not.
60. The raw materials used for the manufacture of Portland cement are
(a) Lime, silies and sulphur dioxide
(b) Lime, silica and carbon dioxide
(c) Lime, silica and alumina
(d) Lime, silica and boric acid
61. Which one of the following statements about water is not true?
(a) Hydrogen bonds are present in liquid water.
(b) Water has a high boiling point.
(c) Water has a high heat of fusion.
(d) Water is a non-polar molecule.
62. A sample of ‘soft soap contains
63. If an object moves at a non-zero constant Acceleration for a certain interval of time, then the distance it covers in that time
(a) depends on its initial velocity.
(b) is independent of its initial velocity.
(c) increases linearly with time.
(d) depends on its initial displacement.
64. A solid disc and a solid sphere have the same mass and same radius. Which one has the higher moment of inertia about its centre of mass?
(a) The disc
(b) The sphere
(c) Both have the same moment of inertia
(d) The information provided sufficient to answer the question
65. Two substances of densities ρ1, and ρ2, are mixed in equal volume and their relative density is 4. When they are mixed in equal masses, relative density is 3. The values of ρ1, and ρ2 respectively are
(a) 6, 2
(b) 3, 5
(c) 12, 4
(d) 9, 3
66. A car starts from Bengaluru, goes 50 km in a straight line towards south, immediately turns around and returns to Bengaluru. The time taken for this round trip is 2 hours. The magnitude of the average velocity of the ear for this round trip
(a) is 0.
(b) is 50 km/hr.
(c) is 25 km/hr.
(d) cannot be calculated without knowing acceleration.
67. “The sum of emfs and potential differences around a closed loop equals zero” is a consequence of
(a) Ohm’s law.
(b) Conservation of charge.
(c) Conservation of momentum.
(d) Conservation of energy.
68. A student measures certain lengths using a meter scale having least count equal to 1 mm. Which one of the following measurements is more precise ?
(a) 0.50 mm
(b) 29.07 cm
(c) 0.925 m
(d) 910 mm
69. If the work done on the system or by the system is zero, which one of the following statements for a gas kept at a certain temperature is correct?
(a) Change in internal energy of the system is equal to flow of heat in or out of the system.
(b) Change in internal energy of the system is less than heat transferred.
(c) Change in internal energy of the system is more than the heat flow.
(d) Cannot be determined.
70. Consider the following part of an electric circuit :
The total electrical resistance in the given part of the electric circuit is
(a) 15/8 ohm
(b) 15/7 ohm
(c) 15 ohm
(d) 17/3 ohm