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
91
What is the main function of 'Antiseptics'?
Answer:
To kill or inhibit the growth of microorganisms on living tissue
Antiseptics are antimicrobial substances that are applied to living tissue/skin to reduce the possibility of infection. Examples include rubbing alcohol or iodine used on a cut. Disinfectants are similar but are too harsh for skin and are used on objects.
92
What happens to the electron affinity as we move from left to right across a period?
Answer:
It generally becomes more negative (increases)
Electron affinity is the energy released when an electron is added. Across a period, nuclear charge increases and atomic size decreases, making the nucleus better at attracting an incoming electron, thus releasing more energy.
93
Tuberculosis (TB) is a serious infectious disease that mainly affects the lungs. Which microorganism is responsible for TB?
Answer:
Mycobacterium tuberculosis (Bacterium)
Tuberculosis is caused by a specific type of bacterium called Mycobacterium tuberculosis. It is an airborne pathogen that can stay suspended in the air for hours, making it highly transmissible in crowded or poorly ventilated environments.
94
Which of these is a covalent network solid?
Answer:
Diamond
In diamond, each carbon atom is covalently bonded to four other carbon atoms in a continuous 3D giant lattice. This makes it extremely hard with a very high melting point.
95
Which of the following is a physical property of liquids?
Answer:
Ability to flow (viscosity)
Liquids have the ability to flow because their particles can slide over each other while remaining in contact. This property is quantified as viscosity (resistance to flow).
96
Electronegativity _______ down a group.
Answer:
Decreases
Down a group, atomic size increases and the shielding effect increases. This makes the nucleus less effective at attracting shared electrons in a bond, thus decreasing electronegativity.
97
What is the shape of a water molecule ($H_2O$)?
Answer:
Bent (V-shaped)
Although the oxygen atom has four electron pairs (two bonding, two lone) arranged tetrahedrally, the molecular shape—the position of the atoms—is bent or V-shaped with an angle of about 104.5 degrees.
98
Down a group, the metallic character of elements:
Answer:
Increases
Metallic character is the tendency to lose electrons. As we move down a group, atomic size increases and ionization energy decreases, making it easier for atoms to lose valence electrons, thus increasing metallic character.
99
The conversion of a gas into a liquid is called:
Answer:
Condensation
Condensation is the change of the physical state of matter from gas phase into liquid phase. It usually occurs when a gas is cooled or compressed.
100
Which of the following describes a 'pandemic'?
Answer:
An epidemic that has spread over several countries or continents
A pandemic is an outbreak of a disease that occurs on a global scale. The COVID-19 pandemic is a recent example where the virus spread rapidly across every continent, affecting millions of people worldwide.