English (Part – B) (General studies) NDA/NA SOLVED PAPER 2019 (II) (51 to 100)

Total Questions: 50

41. Which one of the following is the major constituent of biogas?

Correct Answer: (c) Methane
Solution:

Biogas usually contains 45-70% methane and 30-45% carbon dioxide. It also contains small amounts of nitrogen, hydrogen sulphide, halogenated compound and organic silicon compounds. Thus, among the given options, methane is the major constituent of biogas.

42. Thyroid gland produces a hormone called ‘thyroxine’ which:

Correct Answer: (c) controls metabolic rate
Solution:

Thyroid gland produces a hormone called thyroxine, which controls the metabolic rate of the body. It acts to increase the basal metabolic rate and affects protein, fat and carbohydrate metabolism affecting how human cells use energetic compounds.

43. Which one of the following is a bacterium that causes disease in the human body?

Correct Answer: (c) Salmonella typhi
Solution:Salmonella typhi is a bacterium which causes typhoid fever in the human body. This fever is contracted by the ingestion of contaminated food and water. Varicella zoster is a virus causing chickenpox.
Trypanosoma gambiense and Plasmodium falciparum are protozoans which cause sleeping- sickness and malaria, respectively in the human body.

44. Which one of the following statements regarding viruses is not true?

Correct Answer: (c) Viruses can synthesise their food through photosynthesis
Solution:

The statement given in option (c) is not true and can be corrected as Viruses do not perform photosynthesis to synthesise their food. They are inert, crystalline structure outside the living cell.
Once they infect a cell, they takeover the machinery of the host cell to replicate themselves, killing the host. Rest of the statements are correct

45. Which one of the following diseases may be caused by the deficiency of vitamin-C?

Correct Answer: (d) Scurvy
Solution:

The deficiency of vitamin-C (ascorbic acid) causes scurvy. This condition is characterised by general weakness, anaemia, gingivitis and skin haemorrhage.

46. Compared to audible sound waves, ultrasound waves have:

Correct Answer: (b) higher frequency
Solution:

Ultrasound waves have higher frequency than audible sound waves. The audible range of sound for human beings is form 20 to 20,000 Hz. Children under the age of 5 and some animals such as dogs can hear upto 25,000 Hz. As people grow older, their ears become less sensitive to higher frequency. Ultrasonic sound of frequency higher than 20,000 Hz, which cannot be heard by human beings.

47. A rigid body of mass 2 kg is dropped from a stationary balloon kept at a height of 50 m from the ground. The speed of the body when it just touches the ground and the total energy when it is dropped from the balloon are respectively.

(Take, acceleration due to gravity, g = 9.8 m /s²)

Correct Answer: (d) √980 ms⁻¹ and 980 J
Solution:

48. The temperature of a place on one sunny day is 113 in Fahrenheit scale. The Kelvin scale reading of this temperature will be:

Correct Answer: (a) 318 K
Solution:

49. Radiations coming from the sun are mostly in the form of:

Correct Answer: (b) light and long wavelength infrared
Solution:

The mode of transfer of heat from one body to another without any actual movement the particles involved and without heating the intervening medium, is called radiation.
For radiation, there is no need of any medium because it is of electromagnetic nature. So, radiation coming from the sun are mostly in form of light and long wavelength infrared.

50. Which of the following are the characteristics of electromagnetic waves?

1. They are elastic waves.
2. They can also move in vacuum.
3. They have electric and magnetic components which are mutually perpendicular
4. They move with a speed equal to 3 lakh meters per second.
Select the correct answer using the codes given below.

Correct Answer: (c) 2 and 3
Solution:

Electromagnetic waves or EM waves are waves that are created as a result of vibrations between an electric field and a magnetic field. They are formed when an electric field comes in contact with a magnetic field. The electric field and magnetic field of an electromagnetic wave are perpendicular (at right angles) to each other. They are also perpendicular to the direction of the EM wave.
These waves travel with a constant velocity of 3.0 × 10⁸ m/s in vacuum. They are deflected neither by the electric field nor by the magnetic field.
Hence-statement 2 and 3 are correct