General Knowledge MCQs
Topic Notes: General Knowledge
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
51
Who invented the safety elevator?
Answer:
Elisha Otis
Otis demonstrated his safety brake in 1854 by cutting the hoisting rope of an elevator he was standing on.
52
Who discovered the HIV virus?
Answer:
Luc Montagnier and Françoise Barré-Sinoussi
They isolated the virus that causes AIDS in 1983 at the Pasteur Institute in Paris.
53
Who invented the mechanical calculator (Pascaline)?
Answer:
Blaise Pascal
Pascal invented the mechanical calculator in 1642 to help his father with tax calculations.
54
Who discovered the main blood groups of the Rh system?
Answer:
Karl Landsteiner
Landsteiner (with Alexander Wiener) discovered the Rhesus factor in 1940, further improving transfusion safety.
55
Who invented the first electric motor?
Answer:
Michael Faraday
Faraday demonstrated the principle of conversion of electrical energy into mechanical energy in 1821.
56
Who discovered the phenomenon of electromagnetic induction?
Answer:
Michael Faraday
Faraday discovered in 1831 that a changing magnetic field creates an electric current in a conductor.
57
Who invented the microscope with a single lens (simple microscope)?
Answer:
Antonie van Leeuwenhoek
Leeuwenhoek handcrafted superior single-lens microscopes that allowed him to see bacteria and protozoa for the first time.
58
Who discovered the existence of gravitational waves?
Answer:
LIGO Collaboration
While Einstein predicted them in 1916, the LIGO collaboration made the first direct observation of gravitational waves in 2015.
59
Who invented the cyclotron (particle accelerator)?
Answer:
Ernest Lawrence
Ernest Lawrence invented the cyclotron in 1929, a device used to accelerate charged particles to high speeds.
60
Who discovered cosmic microwave background radiation?
Answer:
Arno Penzias and Robert Wilson
They accidentally discovered the CMB in 1964, providing strong evidence for the Big Bang theory.