What is a major disadvantage of using nuclear fusion reactors

We have not been able to sustain a controlled fusion reaction for more than a brief moment in time, and of more than a small amount of power.

Only the Sun and stars have controlled fusion reactions, and Hydrogen bombs have uncontrolled fusion reactions.

The problem is in maintaining the extremely high temperature and pressure required to sustain a fusion reaction, while at the same time containing the plasma that results from it.

It is so hot that no container will hold it.

We can build magnetic "bottles" so to speak, but the enormous flux required to do that requires super magnets, and that requires super-conductors and super-cold temperatures.

Placing a super-hot plasma flow within the boundaries of a super-cold magnet is just not something we have accomplished yet.

We are working on it, but, barring any stupendous discovery, I think controlled fusion reactors are at least 50 or a 100 years away.

And I Oop-

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0.11 m/s and 0.28 m/s should be correct

find the surface area of the sphere to the nearest square unit. use a calculator.

a. 254 in.2

b. 64 in.2

c. 127 in.2

d. 1,018 in.2