A car of mass 1000 kg moves with velocity 20 m/s. Kinetic energy is MCQ with Answer and Explanation
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Question #1
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What happens to the atomic number and mass number of a radioactive nucleus when it emits a gamma ray?
Correct Answer: Option C
Explanation:
Gamma emission is the release of high-energy electromagnetic radiation (photons) from a nucleus transitioning from an excited high-energy state to a lower, stable energy state. Gamma rays carry no mass and no electrical charge. Therefore, the emission of a gamma ray does not alter the number of protons (atomic number) or the total number of nucleons (mass number) of the atom.
Gamma emission is the release of high-energy electromagnetic radiation (photons) from a nucleus transitioning from an excited high-energy state to a lower, stable energy state. Gamma rays carry no mass and no electrical charge. Therefore, the emission of a gamma ray does not alter the number of protons (atomic number) or the total number of nucleons (mass number) of the atom.
Question #2
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Spring-mass period in orbiting satellite:
Correct Answer: Option B
Explanation:
T = 2π√(m/k): depends on mass and spring constant only, not gravity. Weightlessness doesn't affect spring force. Memory aid: 'Spring period: independent of g; pendulum period: depends on g'. Oscillations concept frequently tested in competitive exams.
T = 2π√(m/k): depends on mass and spring constant only, not gravity. Weightlessness doesn't affect spring force. Memory aid: 'Spring period: independent of g; pendulum period: depends on g'. Oscillations concept frequently tested in competitive exams.
Question #3
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The phenomenon by which heat is transferred through empty space without the need for a material medium is known as:
Correct Answer: Option D
Explanation:
Thermal radiation is the transfer of heat via electromagnetic waves (primarily infrared). Unlike conduction (which requires physical contact) or convection (which requires fluid movement), radiation can travel through a vacuum. This is how the heat from the Sun reaches the Earth through the vacuum of space.
Thermal radiation is the transfer of heat via electromagnetic waves (primarily infrared). Unlike conduction (which requires physical contact) or convection (which requires fluid movement), radiation can travel through a vacuum. This is how the heat from the Sun reaches the Earth through the vacuum of space.
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