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
151
What is the mass of one mole of Carbon-12 atoms?
Answer:
12 grams
The mole is defined such that one mole of Carbon-12 has a mass of exactly 12 grams. This is known as the molar mass.
152
At constant pressure, the volume of a gas is directly proportional to its absolute temperature. This is known as:
Answer:
Charles's Law
Charles's Law states that for a fixed mass of gas at constant pressure, $V/T = k$. This means volume increases linearly with temperature (measured in Kelvin).
153
Antibiotics are powerful medicines, but they are only effective against which group of pathogens?
Answer:
Bacteria
Antibiotics work by targeting specific biological structures in bacteria, such as the cell wall or bacterial ribosomes. Because viruses lack these structures and rely on host cells for replication, antibiotics have no effect on viral infections.
154
Which type of solid is held together by a 'sea of delocalized electrons'?
Answer:
Metallic solid
In metallic bonding, metal atoms release their valence electrons into a common pool. These delocalized electrons move freely throughout the structure, which explains conductivity and malleability.
155
What is the process called when a substance changes directly from a solid to a gas?
Answer:
Sublimation
Sublimation is the transition of a substance directly from the solid to the gas phase without passing through the intermediate liquid phase. Common examples include dry ice (solid $CO_2$) and naphthalene balls.
156
The vertical columns in the Periodic Table are called:
Answer:
Groups
Groups (or families) are vertical columns containing elements with the same number of valence electrons. Because chemical behavior is determined by valence electrons, elements in the same group exhibit similar chemical properties.
157
Which of these is a benefit of combining multiple vaccines into one shot (like the MMR or DTaP)?
Answer:
It reduces the number of injections a child needs and increases the likelihood of completing the schedule
Combination vaccines are highly efficient. They provide protection against several diseases at once, which means fewer clinic visits and less stress for children and parents, leading to higher overall vaccination rates in the population.
158
Which of the following describes the primary mechanism of action for Penicillin against bacteria?
Answer:
Interference with cell wall synthesis
Penicillin works by interfering with the synthesis of peptidoglycan, a critical component of the bacterial cell wall. By preventing the cross-linking of this layer, the cell wall becomes weak and the bacterium eventually bursts due to osmotic pressure (lysis).
159
Elements of the f-block are placed separately at the bottom of the Periodic Table to:
Answer:
Prevent the table from becoming too wide
The Lanthanide and Actinide series are placed at the bottom primarily for structural symmetry and to keep the table's width manageable for printing and viewing.
160
The energy required to remove an electron from the outermost shell of an isolated gaseous atom is:
Answer:
Ionization Energy
Ionization energy measures how strongly an atom holds onto its electrons. It generally increases across a period (due to increasing nuclear charge) and decreases down a group (due to increasing atomic size and shielding).