MCQ 131
Which of the following particles has no charge?
A) Proton
B) Neutron
C) Electron
D) Positron
Answer: B) Neutron.
Explanation: Neutrons are neutral particles found in the nucleus of an atom and do not carry any charge.
MCQ 132
What type of electromagnetic radiation has the shortest wavelength?
A) Infrared
B) Ultraviolet
C) X-rays
D) Gamma rays
Answer: D) Gamma rays.
Explanation: Gamma rays have the shortest wavelength and the highest energy of all types of electromagnetic radiation.
MCQ 133
Which quantum number is associated with the orientation of the electron’s spin?
A) Principal quantum number (n)
B) Azimuthal quantum number (l)
C) Magnetic quantum number (mₗ)
D) Spin quantum number (s)
Answer: D) Spin quantum number (s).
Explanation: The spin quantum number (s) indicates the direction of the intrinsic spin of an electron, which can be either +1/2 or -1/2.
MCQ 134
What is the main limitation of the Bohr model of the atom?
A) It only applies to hydrogen.
B) It cannot explain the spectra of multi-electron atoms.
C) It assumes electrons travel in fixed orbits.
D) All of the above.
Answer: D) All of the above.
Explanation: The Bohr model is limited as it is only applicable to hydrogen, cannot explain multi-electron spectra, and assumes fixed orbits for electrons.
MCQ 135
What is the fundamental principle of quantum superposition?
A) A particle can only exist in one state at a time.
B) A particle can exist in multiple states simultaneously.
C) A particle’s position can be precisely determined.
D) A particle’s energy is quantized.
Answer: B) A particle can exist in multiple states simultaneously.
Explanation: Quantum superposition states that a quantum system can exist in multiple states at once until it is measured.
MCQ 136
Which of the following is true about the Heisenberg Uncertainty Principle?
A) It allows precise measurement of both position and momentum.
B) It limits the accuracy of simultaneously measuring position and momentum.
C) It applies only to macroscopic objects.
D) It is a result of classical physics.
Answer: B) It limits the accuracy of simultaneously measuring position and momentum.
Explanation: The Heisenberg Uncertainty Principle highlights the inherent limitations in measuring certain pairs of physical properties simultaneously.
MCQ 137
What is the term used for the probability density of finding an electron in an atom?
A) Wave function
B) Quantum state
C) Orbit
D) Orbital
Answer: A) Wave function.
Explanation: The wave function provides the probability density for the location of an electron within an atom.
MCQ 138
Which particle is responsible for the chemical behavior of an atom?
A) Neutron
B) Proton
C) Electron
D) Nucleus
Answer: C) Electron.
Explanation: Electrons, especially those in the outermost shell, determine the chemical reactivity and bonding behavior of an atom.
MCQ 139
What type of orbitals are filled after the 4s orbital in the Aufbau principle?
A) 3d
B) 4p
C) 4d
D) 5s
Answer: A) 3d.
Explanation: According to the Aufbau principle, the 3d orbitals are filled after the 4s orbital due to their energy levels.
MCQ 140
Which of the following is a result of the wave-particle duality of matter?
A) Electrons have fixed positions.
B) Light behaves only as a wave.
C) Electrons can exhibit both particle and wave characteristics.
D) Atoms have a solid structure.
Answer: C) Electrons can exhibit both particle and wave characteristics.
Explanation: Wave-particle duality means that electrons can behave as both particles and waves, depending on the experimental conditions.
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