Q. What is the main reason for the appearance of a diffraction pattern when light passes through a narrow slit?
A.
Interference of light waves
B.
Refraction of light
C.
Absorption of light
D.
Reflection of light
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Solution
The diffraction pattern arises due to the interference of light waves that spread out after passing through the slit.
Correct Answer:
A
— Interference of light waves
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Q. What is the main reason for the existence of geometric isomers?
A.
Presence of double bonds
B.
Presence of single bonds
C.
Presence of chiral centers
D.
Presence of functional groups
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Solution
Geometric isomers arise due to restricted rotation around double bonds.
Correct Answer:
A
— Presence of double bonds
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Q. What is the main reason for the occurrence of seasons on Earth?
A.
Distance from the Sun
B.
Tilt of the Earth's axis
C.
Revolution around the Sun
D.
Rotation of the Earth
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Solution
The main reason for the occurrence of seasons on Earth is the tilt of the Earth's axis, which affects the angle of sunlight received.
Correct Answer:
B
— Tilt of the Earth's axis
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Q. What is the main reason for the stability of aromatic compounds?
A.
High molecular weight
B.
Presence of double bonds
C.
Resonance energy
D.
Hydrogen bonding
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Solution
The stability of aromatic compounds is primarily due to resonance energy, which arises from the delocalization of pi electrons across the ring.
Correct Answer:
C
— Resonance energy
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Q. What is the main reason for the stability of atomic nuclei?
A.
Electromagnetic force
B.
Gravitational force
C.
Strong nuclear force
D.
Weak nuclear force
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Solution
The stability of atomic nuclei is primarily due to the strong nuclear force, which binds protons and neutrons together.
Correct Answer:
C
— Strong nuclear force
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Q. What is the main reason for the stability of benzene?
A.
Presence of double bonds
B.
Resonance
C.
Hydrogen bonding
D.
Ionic interactions
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Solution
The stability of benzene arises from resonance, where the electrons are delocalized over the ring structure, lowering the overall energy.
Correct Answer:
B
— Resonance
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Q. What is the main reason for the stability of the electron in an atom? (2019)
A.
Electrostatic attraction to the nucleus
B.
High energy levels
C.
Quantum tunneling
D.
Magnetic forces
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Solution
The stability of the electron in an atom is primarily due to the electrostatic attraction between the negatively charged electrons and the positively charged nucleus.
Correct Answer:
A
— Electrostatic attraction to the nucleus
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Q. What is the main reason for the stability of the electron orbits in an atom according to the Bohr model? (2019)
A.
Electrons are stationary.
B.
Electrons are attracted to the nucleus.
C.
Electrons have quantized energy levels.
D.
Electrons are repelled by each other.
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Solution
In the Bohr model, electrons occupy quantized energy levels, which leads to stable orbits around the nucleus.
Correct Answer:
C
— Electrons have quantized energy levels.
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Q. What is the main reason for the stability of the electron orbits in an atom?
A.
Centripetal force
B.
Electrostatic force
C.
Quantum mechanics
D.
All of the above
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Solution
The stability of the electron orbits in an atom is primarily explained by quantum mechanics.
Correct Answer:
C
— Quantum mechanics
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Q. What is the main reason for the stability of the nucleus in an atom?
A.
Electromagnetic force
B.
Gravitational force
C.
Strong nuclear force
D.
Weak nuclear force
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Solution
The stability of the nucleus is primarily due to the strong nuclear force, which binds protons and neutrons together.
Correct Answer:
C
— Strong nuclear force
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Q. What is the main reason for the stability of the nucleus?
A.
Electromagnetic force
B.
Gravitational force
C.
Strong nuclear force
D.
Weak nuclear force
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Solution
The stability of the nucleus is primarily due to the strong nuclear force, which binds protons and neutrons together.
Correct Answer:
C
— Strong nuclear force
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Q. What is the main reason that gases fill their containers completely? (2023)
A.
Particles are tightly packed
B.
Particles are in fixed positions
C.
Particles move freely and rapidly
D.
Particles have high density
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Solution
Gases fill their containers completely because their particles move freely and rapidly, spreading out to occupy the available space.
Correct Answer:
C
— Particles move freely and rapidly
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Q. What is the main reason that gases have low density compared to solids and liquids?
A.
High temperature
B.
Low pressure
C.
Large particle separation
D.
High kinetic energy
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Solution
Gases have low density because their particles are far apart, leading to a larger volume for the same mass.
Correct Answer:
C
— Large particle separation
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Q. What is the main reason that solids maintain their shape? (2023)
A.
Particles are in constant motion
B.
Particles are tightly packed and vibrate in place
C.
Particles are loosely arranged
D.
Particles have high kinetic energy
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Solution
Solids maintain their shape because their particles are tightly packed and can only vibrate in place, preventing them from flowing.
Correct Answer:
B
— Particles are tightly packed and vibrate in place
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Q. What is the main reproductive structure of angiosperms? (2021)
A.
Cone
B.
Flower
C.
Sporangium
D.
Thallus
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Solution
The main reproductive structure of angiosperms is the flower, which facilitates reproduction through pollination.
Correct Answer:
B
— Flower
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Q. What is the main role of antioxidants in nutrition?
A.
Provide energy
B.
Support immune function
C.
Prevent oxidative stress
D.
Aid digestion
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Solution
Antioxidants help prevent oxidative stress by neutralizing free radicals in the body.
Correct Answer:
C
— Prevent oxidative stress
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Q. What is the main role of dietary fiber in human health? (2021)
A.
Increase cholesterol
B.
Aid digestion
C.
Provide energy
D.
Enhance taste
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Solution
Dietary fiber aids digestion by promoting regular bowel movements and preventing constipation.
Correct Answer:
B
— Aid digestion
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Q. What is the main site of nutrient absorption in the digestive system? (2020)
A.
Mouth
B.
Stomach
C.
Small intestine
D.
Large intestine
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Solution
The small intestine is the main site for the absorption of nutrients.
Correct Answer:
C
— Small intestine
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Q. What is the main site of protein digestion in the digestive system? (2021)
A.
Mouth
B.
Stomach
C.
Small intestine
D.
Large intestine
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Solution
Protein digestion primarily occurs in the stomach, where pepsin breaks down proteins into peptides.
Correct Answer:
B
— Stomach
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Q. What is the main site of protein digestion? (2021)
A.
Mouth
B.
Stomach
C.
Small intestine
D.
Large intestine
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Solution
Protein digestion begins in the stomach, where pepsin breaks down proteins into peptides.
Correct Answer:
B
— Stomach
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Q. What is the main source of alkanes?
A.
Coal
B.
Natural gas
C.
Petroleum
D.
Biomass
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Solution
The main source of alkanes is petroleum, which contains a mixture of hydrocarbons.
Correct Answer:
C
— Petroleum
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Q. What is the main source of freshwater on Earth? (2019)
A.
Rivers
B.
Lakes
C.
Glaciers
D.
Groundwater
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Solution
Glaciers are the main source of freshwater on Earth, storing about 68.7% of the world's freshwater supply.
Correct Answer:
C
— Glaciers
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Q. What is the main source of nitrogen oxides in the atmosphere?
A.
Volcanic eruptions
B.
Vehicle emissions
C.
Industrial processes
D.
Agricultural activities
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Solution
Vehicle emissions are the main source of nitrogen oxides (NOx) in the atmosphere.
Correct Answer:
B
— Vehicle emissions
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Q. What is the main source of omega-3 fatty acids? (2021)
A.
Fish oil
B.
Butter
C.
Coconut oil
D.
Olive oil
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Solution
Fish oil is a rich source of omega-3 fatty acids, which are important for heart health and brain function.
Correct Answer:
A
— Fish oil
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Q. What is the main source of ozone depletion? (2021)
A.
Carbon dioxide
B.
Chlorofluorocarbons (CFCs)
C.
Methane
D.
Nitrous oxide
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Solution
Chlorofluorocarbons (CFCs) are the primary substances responsible for ozone layer depletion.
Correct Answer:
B
— Chlorofluorocarbons (CFCs)
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Q. What is the main source of ozone layer depletion? (2021)
A.
Carbon dioxide
B.
Chlorofluorocarbons (CFCs)
C.
Methane
D.
Nitrous oxide
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Solution
Chlorofluorocarbons (CFCs) are the primary substances responsible for the depletion of the ozone layer.
Correct Answer:
B
— Chlorofluorocarbons (CFCs)
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Q. What is the main source of plastic pollution in oceans? (2021)
A.
Industrial waste
B.
Agricultural runoff
C.
Single-use plastics
D.
Sewage discharge
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Solution
Single-use plastics, such as bags and bottles, are a major contributor to plastic pollution in oceans.
Correct Answer:
C
— Single-use plastics
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Q. What is the main source of sulfur dioxide in the atmosphere?
A.
Volcanic eruptions
B.
Automobile emissions
C.
Industrial processes
D.
All of the above
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Solution
Sulfur dioxide is released from various sources including volcanic eruptions, automobile emissions, and industrial processes.
Correct Answer:
D
— All of the above
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Q. What is the main storage form of carbohydrates in animals?
A.
Starch
B.
Glycogen
C.
Cellulose
D.
Chitin
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Solution
Glycogen is the main storage form of carbohydrates in animals, while starch is the storage form in plants.
Correct Answer:
B
— Glycogen
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Q. What is the main structural component of plant cell walls?
A.
Starch
B.
Glycogen
C.
Cellulose
D.
Chitin
Show solution
Solution
Cellulose is the main structural component of plant cell walls.
Correct Answer:
C
— Cellulose
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