A typical LED converts electrical energy into light with efficiency around
A. 80-90%
B. 10%
C. 100%
D. 50-60%
Answer: Option A
Solution (By JKSSB Mock Tests)
LEDs are highly efficient, converting ~80-90% of electrical energy into light, rest heat. Incandescent bulbs ~10% efficient. LED long life, low power. Blue LED Nobel prize 2014.
Explanation:
Isaac Newton formulated the universal law of gravitation in his Principia Mathematica (1687), stating F = Gm₁m₂/r². Galileo studied falling bodies; Kepler derived planetary motion laws; Einstein developed general relativity (gravity as spacetime curvature). Memory aid: 'Newton = gravity apple story'. This history-based question tests knowledge of key scientific contributions, frequently appearing in competitive exams. Always associate scientists with their specific discoveries to avoid confusion between classical and modern physics pioneers.
Explanation:
Sir C.V. Raman discovered inelastic scattering of light (Raman effect) in 1928, received Nobel in 1930. Used to study molecular structure. Photoelectric effect: Einstein. Electron: J.J. Thomson. Fission: Hahn and Strassmann.
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