General Ability NDA/NA Solved Paper 2020-I (101-150)

Total Questions: 50

31. The part of the human eye on which the image is formed is

Correct Answer: (c) retina
Solution:

When the light enters the human eye through the cornea; it then passes through the aqueous humor, the lens and the vitreous humor. Then the image is formed on
the retina of the eye.

The eye is considered by most neuroscientists as actually part of the brain. It consists of a small spherical globe ofabout 2cm in diameter, which is free to rotate under the control of 6 extrinsic muscles.

Light enters the eye through the transparent cornea, passes through the aqueous humor, the lens, and the vitreous
humor, where it finally forms an image on the retina.

32. Consider the following image:

A proton enters a magnetic field at right angles to it, as shown above. The direction of force acting on the proton will be

Correct Answer: (d) into the page
Solution:

We know that both the directions are perpendicular, thus for force direction =? Using Fleming's left hand rule, Direction of force is perpendicular to the direction of magnetic field and current. Thus direction of force is opposite to electron motion into the page at 90°.

33. Which one of the following statements about sound is NOT correct?

Correct Answer: (b) Sound waves are transverse waves
Solution:

The sensation felt by our ears is called sound. It is a form of energy which makes us hear. Sound travels in the form of wave. Longitudinal Waves: A wave in which the particles ofthe
medium vibrate back and forth in the 'same direction' in which the wave is moving. Medium can be solid, liquid or gases.

Therefore, sound waves are longitudinal waves. Sound is a longitudinal wave which consists of compressions and rarefactions travelling through a medium. Transverse Waves: A wave in which the particles of the medium vibrate up and down 'at right angles' to the direction in which the wave is moving. These waves are produced only in a solids and liquids but not in gases.

34. When the short circuit condition occurs, the current in the circuit

Correct Answer: (c) increases substantially
Solution:

Normal Short Circuit is when a hot wire carrying current touches a neutral wire. When that happens, the resistance will go down instantly and a large volume of current will flow through an unexpected pathway.

35. Which one ofthe following is NOT a component ofhuman male reproductive system?

Correct Answer: (a) Cervix
Solution:

The male reproductive system includes the penis. scrotum, testes, epididymis, vas deferens, prostate, and seminal vesicles.

  • The penis and the urethra are part ofthe urinary and reproductive systems.
  • The scrotum, testes (testicles), epididymis, vas deferens, seminal vesicles, and prostate comprise the rest ofthe reproductive system.

The cervix is a cylinder-shaped neck of tissue that connects the vagina and uterus. Located at the lowermost portion ofthe uterus, the cervix is composed primarily of fibromuscular tissue. Thus Cervix is not a part of male reproductive system.

36. Which one of the following is NOT a reason of decrease in biodiversity?

Correct Answer: (c) Maintaining sacred groves
Solution:

The main cause of the loss of biodiversity can be attributed to the influence of human beings on the world's ecosystem, In fact human beings have deeply altered the environment, and have modified the territory, exploiting the species directly, for example by fishing and hunting, changing the biogeochemical cycles and transferring species from one area to another of the Planet.
Alteration and loss of the habitats; Pollution; Climate change and Overexploitation of resources are main threats of environment.

37. Which one ofthe following is NOT a cause of depletion in groundwater?

Correct Answer: (a) Afforestation
Solution:

The two main causes of Depletion of Water Table are Deforestation and Over-pumping of groundwater. Constructions of large scale concrete buildings are also one of the causes of Depletion of Water.

38. Which one of the following types of radiations has the smallest wavelength?

Correct Answer: (d) X-rays
Solution:

X- Rays have smaller wavelengths and therefore higher energy than ultraviolet waves. Microwaves are the highest frequency of radio waves. Their wavelength is only a few centimetres long.

Infrared lies between the visible and microwave portions of the electromagnetic spectrum. Shorter, near infrared waves are not hot at all - in fact you cannot even feel them. Visible waves are the only electromagnetic waves we can see.

We see these waves as the colors of the rainbow. Each color has a different wavelength. Red has the longest wavelength and violet has the shortest wavelength. When all the waves are seen together, they make white light.

39. The instrument used for detecting the presence of electric current in a circuit is

Correct Answer: (b) Galvanometer
Solution:

A galvanometer is an electromechanical instrument used for detecting and indicating an electric current. A galvanometer works as an actuator, by producing a rotary deflection (of a "pointer"), in response to electric current flowing through a coil in a constant magnetic field.

40. Which one ofthe following is the largest composition in biogas?

Correct Answer: (b) Methane
Solution:

Biogas is produced by anaerobic digestion of fermentation of biodegradable materials such as biomass, manure, sewage, municipal waste, green waste, plant material and energy crops. This type of biogas comprises primarily methane.
Composition of biogas