Answer: The major challenges are as
1) understanding of the plasma: Plasma is a soup like mixture of subatomic particles of different atoms nuclei and electrons that are shattered apart by the temperature at which plasma is formed. further research is needed to understand the behavior of plasma so that it can be put to a proper use.
2) Confinement of plasma: Once we get the plasma we need to hold it so that we can obtain heat from it to drive a steam turbine but the sheer temperature of plasma is in millions of Celsius thus currently making it impossible to confine conventionally. Scientists use a loop of electric and magnetic fields to keep it in circulatory like manner so that it can be studied.
3) finally to obtain electricity from the plasma it should be stable to produce electricity. But currently to obtain pressure, temperature so that we have a sustained supply is highly difficult in technical and economical aspects.
Inertial confinement: In order to get the nuclei of atoms close enough for fusion this type of method used compression of the nuclei into highly small volumes.This is accomplished by use of lasers which are directed towards the fuel pellets that implode and travel towards other nuclei making fusion possible. It's main advantage is that it requires lesser time to initiate fusion but the disadvantage being that a large power is used to fire the lasers and the lasers should all hit the small target.
Magnetic Confinement: In this method we use a magnetic and electric fields in a properly designed space to keep the plasma in motion. In motion the nuclei of the atoms come close enough to initiate fusion.It's advantage being less power is required to start the process as compared to inertial confinement and the disadvantage being that plasma confinement is currently not properly understood.
Answer:
M. Magnetism is a property of individual atoms.
Explanation:
when a magnet is broken into pieces the new pieces behave like the original magnet this observation shows that magnetism is the property of individual atoms.
By definition, the density of an object is given by:

Where,
M: mass of the object
V: volume of the object
Since the mass and volume of an object are numerical values greater than zero, then it follows that:

It is important to respect the units of each measure.
For this case we can use the grams for the mass and cubic centimeters for the volume.
Answer:
A possible value for density is given by:

<span>As the charged insulating rod approaches the sphere (not in contact), free electrons in the sphere move. If the rod is negatively charged, free electrons move to the side of the sphere opposite the side with the rod. If the rod is positively charged, the free electron moves to the side of the sphere with the rod. In either case, the region of the sphere near the rod acquires a charge with the sign opposite to that on the rod.
a. Since opposedly charged objects always attract each other, the rod and ball always experience mutual attractive forces.
b. Since
the side of the sphere near the bar always has the opposite charge to
the charge of the rod, the rod and the sphere always attract each other. <span>They do not repel each other.</span></span>