Question

The scientific principle useful for the working of a fusion test reactor is:

• A. Trapping and cooling of atoms by laser beams and magnetic fields
• B. Controlled nuclear fission
• C. Magnetic confinement of plasma
• D. Wave nature of electrons

Hint:

Remember: Fusion reactors use extremely strong magnetic fields to confine hot plasma. Tokamak reactors work on the principle of magnetic confinement.

Answer 1

The Correct Option is C

Concept: Nuclear fusion is the process in which two light nuclei combine to form a heavier nucleus with the release of an enormous amount of energy. Fusion is the source of energy in stars, including the Sun. To achieve fusion on Earth, extremely high temperatures of the order of millions of degrees Kelvin are required. At such temperatures, matter exists in the plasma state. Since no material container can withstand such temperatures, special methods are required to confine the plasma.

Step 1: Understand the requirement for fusion reactions. Fusion reactions involve positively charged nuclei. These nuclei repel each other due to electrostatic forces. To overcome this repulsion and bring the nuclei sufficiently close for fusion, the fuel must be heated to extremely high temperatures. At these temperatures, electrons are stripped from atoms and a plasma is formed.

Step 2: Understand the problem of plasma containment. The temperature inside a fusion reactor may reach tens of millions of degrees Kelvin. No ordinary material can contain such hot matter without melting or vaporizing. Therefore, direct physical contact between plasma and reactor walls must be avoided.

Step 3: Study the principle used in fusion reactors. Since plasma contains charged particles, magnetic fields can exert forces on them. Strong magnetic fields are therefore used to confine and control the motion of plasma. This technique is called magnetic confinement. Devices such as Tokamaks and Stellarators operate on this principle.

Step 4: Analyze the options. Option (A) is related to laser cooling and trapping techniques. Option (B) refers to nuclear fission, not fusion. Option (D) is unrelated to plasma confinement. Only magnetic confinement of plasma is directly used in fusion reactors.

Step 5: State the answer. Therefore, the scientific principle used in fusion test reactors is \[ \boxed{\text{Magnetic confinement of plasma}} \]