Which scientific instrument is used specifically for measuring very high temperatures, such as the surface temperature of the Sun or inside a furnace, from a distance? MCQ with Answer and Explanation
Which scientific instrument is used specifically for measuring very high temperatures, such as the surface temperature of the Sun or inside a furnace, from a distance?
A. Pyrometer
B. Cryometer
C. Calorimeter
D. Bolometer
Answer: Option A
Solution (By JKExamLibrary)
A pyrometer is a non-contact thermometer used to measure high temperatures. It operates on the principle of thermal radiation (Stefan-Boltzmann law or Wien's law), measuring the intensity or spectrum of electromagnetic radiation emitted by the extremely hot object. A cryometer measures very low temperatures, and a calorimeter measures heat capacity.
Explanation:
Michael Faraday discovered electromagnetic induction in 1831. He demonstrated that a changing magnetic field could induce an electric current in a nearby circuit. This groundbreaking discovery laid the foundation for all modern electric generators and transformers. Tesla contributed to AC systems, Edison to DC systems, and Hertz proved the existence of radio waves.
Explanation:
Resistance R = V²/P = 220²/100 = 484 Ω. At 110 V, P = V²/R = 110²/484 = 12100/484 = 25 W. Assuming resistance constant. Power reduces to quarter when voltage halved (P ∝ V² for fixed R).
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