SSC General Science 2 — Questions and Answers
Question 1: The pH of pure water at 25°C is:
- 0
- 7 (Correct answer)
- 14
- 5
Correct answer: 7
Pure water is neutral with a pH of exactly 7, meaning equal concentrations of H⁺ and OH⁻ ions.
Question 2: Which part of the human eye contains the photoreceptors (rods and cones)?
- Cornea
- Lens
- Retina (Correct answer)
- Pupil
Correct answer: Retina
The retina is the light-sensitive layer at the back of the eye containing rods (for dim light) and cones (for color vision).
Question 3: What type of mirror is used in the rear-view mirrors of vehicles?
- Concave mirror
- Plane mirror
- Convex mirror (Correct answer)
- Parabolic mirror
Correct answer: Convex mirror
Convex mirrors provide a wider field of view and always form virtual, erect, and diminished images, making them ideal for rear-view mirrors.
Question 4: Rusting of iron is an example of which type of chemical reaction?
- Reduction
- Displacement
- Oxidation (Correct answer)
- Decomposition
Correct answer: Oxidation
Rusting involves iron reacting with oxygen and moisture to form iron oxide (Fe₂O₃), which is an oxidation reaction.
Question 5: Which blood group is considered the 'universal donor'?
- AB+
- O+
- A-
- O- (Correct answer)
Correct answer: O-
O- (O negative) is the universal donor because it lacks A, B, and Rh antigens, making it compatible with all blood types.
Question 6: The unit used to measure the frequency of sound waves is:
- Decibel
- Hertz (Correct answer)
- Joule
- Pascal
Correct answer: Hertz
Hertz (Hz) is the SI unit of frequency, defined as one cycle per second, and is used to measure sound wave frequency.
Question 7: Which vitamin is produced by the human skin when exposed to sunlight?
- Vitamin A
- Vitamin B12
- Vitamin C
- Vitamin D (Correct answer)
Correct answer: Vitamin D
Vitamin D is synthesized in the skin when ultraviolet B (UVB) radiation from sunlight converts 7-dehydrocholesterol to Vitamin D₃.
SSC General Science 2
The pH of pure water at 25°C is: