Showing 51–60 of 419 questions
Q.51
Hard
General Science
What is the process by which an electric current is generated using a magnetic field?
A
Magnetization
B
Electromagnetic induction
C
Polarization
D
Ionization
Correct Answer:
B. Electromagnetic induction
Explanation:
Electromagnetic induction is the process where a changing magnetic field produces an electric current, as discovered by Faraday.
Q.52
Hard
General Science
Which gas is used in welding and cutting of metals?
A
Nitrogen
B
Oxygen
C
Acetylene
D
Hydrogen
Correct Answer:
C. Acetylene
Explanation:
Acetylene (C₂H₂) is commonly used in oxy-acetylene welding and cutting due to its high flame temperature of about 3,300°C.
Q.53
Medium
General Science
In Newton's third law of motion, if object A exerts a force on object B, what does object B do?
A
Exerts an equal and opposite force on A
B
Exerts a smaller force on A
C
Exerts no force on A
D
Exerts a greater force on A
Correct Answer:
A. Exerts an equal and opposite force on A
Explanation:
Newton's third law states that for every action, there is an equal and opposite reaction. Forces always occur in pairs.
Q.54
Easy
General Science
Which of the following is a non-renewable energy source?
A
Solar energy
B
Wind energy
C
Coal
D
Hydroelectric energy
Explanation:
Coal is a fossil fuel and non-renewable energy source. Solar, wind, and hydroelectric are renewable sources.
Q.55
Easy
General Science
Which of the following is the hardest naturally occurring substance on Earth?
A
Graphite
B
Diamond
C
Quartz
D
Feldspar
Correct Answer:
B. Diamond
Explanation:
Diamond is the hardest naturally occurring substance, rating 10 on the Mohs hardness scale.
Q.56
Easy
General Science
What is the speed of light in vacuum (approximately)?
A
3 × 10^8 m/s
B
3 × 10^6 m/s
C
3 × 10^10 m/s
D
3 × 10^5 m/s
Correct Answer:
A. 3 × 10^8 m/s
Explanation:
The speed of light in vacuum is approximately 3 × 10^8 meters per second or 300,000 km/s.
Q.57
Easy
General Science
Which hormone regulates blood sugar levels in the human body?
A
Adrenaline
B
Thyroxine
C
Insulin
D
Cortisol
Correct Answer:
C. Insulin
Explanation:
Insulin, produced by the pancreas, regulates blood glucose levels by promoting glucose uptake and storage.
Q.58
Easy
General Science
What is the chemical formula of common salt?
A
KCl
B
NaCl
C
CaCl2
D
MgCl2
Explanation:
Common salt is sodium chloride (NaCl), composed of sodium and chlorine ions.
Q.59
Medium
General Science
Which of the following is the largest organ in the human body by mass?
A
Heart
B
Brain
C
Liver
D
Lung
Explanation:
The liver is the largest internal organ by mass, weighing approximately 1.5 kg in adults.
Q.60
Medium
General Science
What happens to the density of water when it freezes into ice?
A
Density increases
B
Density decreases
C
Density remains the same
D
Density becomes zero
Correct Answer:
B. Density decreases
Explanation:
Ice has lower density than water, which is why ice floats on water. Water expands when it freezes.
