A fuse wire should have MCQ with Answer and Explanation
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Question #1
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The centre of mass of a two-particle system lies on the line joining them, closer to
Question #2
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The essential condition required for Laser action to occur in a medium is known as:
Correct Answer: Option D
Explanation:
Laser (Light Amplification by Stimulated Emission of Radiation) requires that more atoms exist in a high-energy excited state than in a lower energy state. This unnatural, non-equilibrium condition is called 'population inversion'. Without it, absorption would dominate over stimulated emission, and the beam would not be amplified.
Laser (Light Amplification by Stimulated Emission of Radiation) requires that more atoms exist in a high-energy excited state than in a lower energy state. This unnatural, non-equilibrium condition is called 'population inversion'. Without it, absorption would dominate over stimulated emission, and the beam would not be amplified.
Question #3
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A radioactive sample has a half-life of 5 years. What fraction of the original active nuclei will remain undecayed after 15 years?
Correct Answer: Option C
Explanation:
The number of half-lives (n) that have passed is total time / half-life = 15 / 5 = 3 half-lives. The fraction of the sample remaining undecayed is given strictly by the formula (1/2)^n. Therefore, the fraction remaining is (1/2)^3 = 1/2 * 1/2 * 1/2 = 1/8.
The number of half-lives (n) that have passed is total time / half-life = 15 / 5 = 3 half-lives. The fraction of the sample remaining undecayed is given strictly by the formula (1/2)^n. Therefore, the fraction remaining is (1/2)^3 = 1/2 * 1/2 * 1/2 = 1/8.
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