General Knowledge (Part – B : english) (NDA/NA SOLVED PAPER 2021-I) (51 to 100)

Total Questions: 50

41. 'Beats' is a phenomenon that occurs when frequencies of two harmonic waves are

Correct Answer: (d) nearly same.
Solution:
  • The beating phenomenon occurs when two harmonic waves of slightly different frequencies are impressed on a body. They are a periodic variation in vibration at a frequency that is the difference between to two frequencies.
    When two sound waves of different frequency approach your ear, the alternating constructive and destructive interference causes the sound to be alternatively soft and loud - a phenomenon which is called "beating" or producing beats.

42. Light waves are incident on an air-glass boundary. Some of the light waves are reflected and some are refracted in the glass. Which one of the following properties is the same for the incident wave and the refracted wave?

Correct Answer: (d) Frequency
Solution:Frequency is the one among the following given options which applies to the demand of the question. It is same for the incident wave and refracted wave.

43. Which one of the following statements is true for a simple harmonic oscillator?

Correct Answer: (b) Force acting is directly proportional to the displacement from the mean position and is in opposite direction.
Solution:In simple harmonic motion, the acceleration of the system and therefore the net force is proportional to the displacement and acts in the opposite direction of the displacement.

44. During seed germination, the part of the embryo which grows into root is

Correct Answer: (a) Radicle.
Solution:The primary root, or radicle, is the first organ to appear when a seed germinates. It grows downward into the soil, anchoring the seedling. In gymnosperms and dicotyledons (angiosperms with two seed leaves), the radicle becomes a taproot. The tip of the root is covered by a mass of loose cells called the root cap.

45. In a typical flower, germinating pollen grains pass through several parts of the gynoecium before they reach the ovule. A list of the parts of gynoecium is given below in different combinations. Choose the combination that represents the correct sequence of pollen tube pathway/journey:

Correct Answer: (b) Stigma, Style, Ovary
Solution:
  • The gynoecium is the innermost whorl of a flower; it consists of (one or more) pistils and is typically surrounded by the pollen-producing reproductive organs, the stamens, collectively called the androecium.
  • Carpels and pistils have three parts: a stigma at the top where the pollen lands; a style and an ovary
  • The correct pathway is Stigma, Style And Ovary

46. If human blood is placed in a 2% detergent solution, what will happen to the RBC?

Correct Answer: (d) The RBC will lyse.
Solution:When human red blood cells (RBCs) are placed in a 2% detergent solution, they will break apart, or lyse. This occurs because the detergent disrupts the cell membrane, which is a lipid bilayer surrounding the RBCs; thus, option (d) is correct.

47. The major source of vitamins and minerals for vegetarians is

Correct Answer: (c) vegetables and fruits.
Solution:Vegatables and fruits are the major source of vitamins and minerals for the vegetarians.

48. If a ray of light enters from a rarer medium to a denser medium at zero angle of incidence, it would

Correct Answer: (b) go straight.
Solution:If a ray of light enters from a rarer medium to a denser medium at a zero angle of incidence, it would pass through without bending and continue in a straight line, as there is no change in direction when the angle of incidence is zero, regardless of the medium change.

49. Mirage is an illustration of

Correct Answer: (d) both refraction and total internal reflection of light.
Solution:
  • A mirage is a naturally occurring optical phenomenon in which light rays bend via refraction to produce a displaced image of distant objects or the sky.
  • When the reflected light ray reaches our eyes, it appears as coming from the sky or tree. This inverted image creates an optical illusion of the presence of water or the presence of islands etc. So the mirage is an example of refraction of light and total internal reflection.

50. Common salt (NaCl) is not used as a raw material for preparation of which one of the following compounds?

Correct Answer: (c) Plaster of Paris
Solution:Sodium carbonate can be obtained by heating baking soda, recrystallization of sodium carbonate gives washing soda. It is also called basic salt. Plaster of Paris is obtained by heating gypsum. Thus NaCl is not used in formation of plaster of paris.