The work function of a metal is 2.3 eV. The threshold frequency for photoelectric emission is approximately: (h = 4.14×10⁻¹⁵ eV·s) MCQ with Answer and Explanation
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Question #1
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Weight of 10 kg mass on Moon (g_moon ≈ g_earth/6) is:
Correct Answer: Option A
Explanation:
Weight W = mg. On Earth: 10×10 = 100 N. On Moon: g_moon ≈ 10/6 ≈ 1.67 m/s². W_moon = 10×1.67 ≈ 16.7 N. Mass remains 10 kg; weight changes with gravity. Memory tip: 'Mass constant; weight ∝ g'. Tests mass-weight distinction and gravity variation, common conceptual question in competitive exams.
Weight W = mg. On Earth: 10×10 = 100 N. On Moon: g_moon ≈ 10/6 ≈ 1.67 m/s². W_moon = 10×1.67 ≈ 16.7 N. Mass remains 10 kg; weight changes with gravity. Memory tip: 'Mass constant; weight ∝ g'. Tests mass-weight distinction and gravity variation, common conceptual question in competitive exams.
Question #2
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The pitch of a sound depends on its
Question #3
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Electromagnetic induction basis for:
Correct Answer: Option D
Explanation:
Induction (changing flux ⇒ EMF): generators (motion ⇒ electricity), transformers (AC voltage conversion). Motors use reverse principle (force on current in field). Memory aid: 'Induction: generators, transformers; motors: Lorentz force'. Device principle frequently tested in competitive electromagnetism sections.
Induction (changing flux ⇒ EMF): generators (motion ⇒ electricity), transformers (AC voltage conversion). Motors use reverse principle (force on current in field). Memory aid: 'Induction: generators, transformers; motors: Lorentz force'. Device principle frequently tested in competitive electromagnetism sections.
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