QUANTUM PHYSICS FUNDAMENTALS - Chapter 10, Exercise 2 Solution
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The Real Combined Length of Every MOSFET Ever Made

PROBLEM
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If a single MOSFET is roughly the width of a modern semiconductor
manufacturing process node (for illustration, treat it as 10
nanometers wide), and real, documented history shows more than 13
sextillion (1.3 x 10^22) MOSFETs had been manufactured by 2018,
calculate the combined real length of every MOSFET manufactured by
that year, laid end to end, in kilometers.

SOLUTION
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Step 1: Calculate total length in nanometers.

    Total length = (number of MOSFETs) x (width per MOSFET)
    Total length = (1.3 x 10^22) x (10 nm)
    Total length = 1.3 x 10^23 nm

Step 2: Convert nanometers to kilometers.

    1 nm = 1 x 10^-12 km

    Total length = (1.3 x 10^23) x (1 x 10^-12) km
    Total length = 1.3 x 10^11 km

ANSWER: Laid end to end, every MOSFET manufactured by 2018 would
stretch approximately 1.3 x 10^11 km - 130 billion kilometers.

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WHY THIS WORKS AS AN ANSWER

For real scale, 130 billion km is roughly 869 times the distance from
the Earth to the Sun (1 astronomical unit is approximately 1.496 x
10^8 km) - meaning this real, illustrative chain of transistors, each
individually far too small to see with the naked eye, would stretch
many times past the orbit of Neptune if laid end to end. This
striking real scale is exactly why the chapter calls the MOSFET the
most numerously manufactured artificial object in human history - a
genuinely staggering real consequence of a piece of quantum physics
(the Pauli exclusion principle, via semiconductor band structure)
being manufactured at an industrial scale most people never stop to
consider.