General Science/Everyday Science MCQs
Topic Notes: General Science/Everyday Science
MCQs and preparation resources for competitive exams, covering important concepts, past papers, and detailed explanations.
Plato
- Biography: Ancient Greek philosopher (427–347 BCE), student of Socrates and teacher of Aristotle, founder of the Academy in Athens.
- Important Ideas:
- Theory of Forms
- Philosopher-King
- Ideal State
41
Evaporation is a surface phenomenon that results in:
Answer:
Cooling of the liquid
Evaporation causes cooling because the high-energy particles escape from the surface, leaving behind particles with lower average kinetic energy, thus lowering the temperature of the remaining liquid.
42
Why are antibiotics ineffective against viruses like the common cold or influenza?
Answer:
Viruses do not have cell walls or metabolic pathways that antibiotics target
Antibiotics target specific bacterial structures (like peptidoglycan cell walls) or machinery (like bacterial ribosomes). Viruses do not have these structures; they are essentially genetic material in a protein coat and use the host's own cellular machinery to replicate.
43
Why do some vaccines, like the Tetanus shot, require 'booster' doses every few years?
Answer:
The level of antibodies and memory cells can decline over time
For certain pathogens, the 'memory' created by the first vaccination is not lifelong. Booster shots are needed to 'remind' the immune system and bring the level of protective antibodies back up to a safe threshold.
44
An atom that has lost one or more electrons is called a/an:
Answer:
Cation
Cations are positively charged ions formed when an atom loses electrons. Since there are now more protons than electrons, the net charge is positive.
45
Which period is the shortest period in the Periodic Table?
Answer:
Period 1
Period 1 is the shortest period as it contains only two elements: Hydrogen and Helium. These elements fill only the first energy level ($n=1$), which can hold a maximum of two electrons.
46
Which of the following scientists first proposed that matter is made of tiny, indivisible particles called 'atoms'?
Answer:
Democritus
Democritus, an Ancient Greek philosopher, first used the term 'atomos' (meaning indivisible) to describe the fundamental building blocks of matter.
47
The tendency of an atom to attract electrons towards itself in a chemical bond is called:
Answer:
Electronegativity
Electronegativity is a relative scale (like the Pauling scale) that indicates an atom's ability to compete for electrons in a covalent bond. It differs from electron affinity, which is the energy change for adding an electron to a neutral atom.
48
Which element has the electron configuration $2, 8, 1$?
Answer:
Sodium
The total number of electrons is $2 + 8 + 1 = 11$. The element with atomic number 11 is Sodium (Na).
49
What happens to the volume of a fixed mass of gas if the pressure is doubled at constant temperature (Boyle's Law)?
Answer:
It is halved
Boyle's Law states that pressure and volume are inversely proportional ($P imes V = k$). If the pressure is doubled, the volume must be reduced by half to maintain the constant value.
50
The diagonal relationship is observed between which pairs of elements?
Answer:
Li and Mg
A diagonal relationship exists between certain elements of the second and third periods (e.g., Li-Mg, Be-Al, B-Si). These pairs have similar charge densities and electronegativities, leading to similar chemical behavior.