# All Questions

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### Why is the voltage negative?

What I don't understand is why the the two voltage sources are subtracted, The graph does not show the orientation of the solar panel so I thought I was to assume they had the same orientation? ...
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### can there be an object which reflects( not illuminates ) electromagnetic waves in the non visible region?

can there be an object which reflects( not illuminates ) electromagnetic waves in the non visible region? If so then will it be appeared to us(humans who can see visible region only) transparent or ...
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### Calculate rotational duration of magnetic levitation inside a vacuum chamber?

Background Numerous examples show rotating pyrolytic graphite (or similar diamagnetic material) that can be moved using a laser. Problem The problem has the following objects: An N52 grade ...
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### What mechanism is responsible for the creation of these dunes on Comet 67P/Churyumov-Gerasimenko?

What mechanism is responsible for the creation of these dunes on Comet 67P/Churyumov-Gerasimenko? The following high resolution picture from ESA's Rosetta mission shows the dunes: At a distance ...
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### Alternating Current/Electromototive Force equaling 0?

All alternating current diagrams are drawn as sinusoidal waves that intercept with x axis. Given our usual sine wave that equals to 0 at 180° it would mean the alternating current would equal to 0. If ...
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### How does independence of the basic bras affect the choice of numbers used to represent a ket?

On page 54 of Dirac's book, The Principles of Quantum Mechanics, he states: Take an orthogonal representation with basic bras $\langle\lambda_1\lambda_2...\lambda_u|$, labelled by parameters ...
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### Extracting times of hits from a composite detector response

I have a detector that registers a sequence of "hits" over a period of time. Each hit produces a signal that has the approximate form ...
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### Sum of static and dynamic pressure in a tube constant?

The sum of static pressure and dynamic pressure is said to be constant along a streamline. Except for energy conservation reasons I don't understand why that is. Static pressure is proportional to ...
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### Principle of electrical machine by vk R mehta complete ebook needed [on hold]

I need the ebook for my exam on Wednesday(expecially dc generator and dc motor chapter)
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### Tensor Notation Puzzle

I have hesitated to ask this question for fear of someone tagging it as a duplicate. It comes close to what others might have asked but I am looking for particular answers to this puzzle. Using ...
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