The escape velocity from Earth's surface is approximately 11.2 km/s. If a planet has twice Earth's radius and same density, its escape velocity will be: MCQ with Answer and Explanation
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Question #1
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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)
Correct Answer: Option C
Explanation:
Photoelectric equation: work function φ = hν₀, where ν₀ is threshold frequency. Thus ν₀ = φ/h = 2.3 eV / (4.14×10⁻¹⁵ eV·s) ≈ 5.555×10¹⁴ Hz ≈ 5.6×10¹⁴ Hz. This direct application tests photoelectric effect fundamentals. Memory aid: 'ν₀ = φ/h; higher work function ⇒ higher threshold frequency'. Competitive exams frequently provide h in eV·s for such calculations. Always ensure units match: eV for φ and h to avoid conversion errors. This problem assesses numerical proficiency in modern physics applications.
Photoelectric equation: work function φ = hν₀, where ν₀ is threshold frequency. Thus ν₀ = φ/h = 2.3 eV / (4.14×10⁻¹⁵ eV·s) ≈ 5.555×10¹⁴ Hz ≈ 5.6×10¹⁴ Hz. This direct application tests photoelectric effect fundamentals. Memory aid: 'ν₀ = φ/h; higher work function ⇒ higher threshold frequency'. Competitive exams frequently provide h in eV·s for such calculations. Always ensure units match: eV for φ and h to avoid conversion errors. This problem assesses numerical proficiency in modern physics applications.
Question #2
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The Nobel Prize in Physics in 1930 was awarded to an Indian scientist for his work on the scattering of light. Identify the scientist.
Correct Answer: Option A
Explanation:
Sir C. V. Raman was awarded the Nobel Prize in Physics in 1930 for discovering the 'Raman Effect'. The Raman effect involves the inelastic scattering of photons by molecules, resulting in a change in wavelength. This discovery proved that light has particle-like characteristics. National Science Day in India (Feb 28) commemorates this discovery.
Sir C. V. Raman was awarded the Nobel Prize in Physics in 1930 for discovering the 'Raman Effect'. The Raman effect involves the inelastic scattering of photons by molecules, resulting in a change in wavelength. This discovery proved that light has particle-like characteristics. National Science Day in India (Feb 28) commemorates this discovery.
Question #3
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A pendulum has time period 2 s. If its length is increased by 4 times, new period is
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