An example of type I superconductor is:

Explanation:

Type I Superconductors

Definition: Type I superconductors are materials that exhibit superconductivity at relatively low critical magnetic fields and transition abruptly from the superconducting state to the normal state. They are characterized by their complete exclusion of magnetic fields (the Meissner effect) and are typically elemental metals.

Working Principle: The phenomenon of superconductivity occurs when a material is cooled below its critical temperature, causing its electrical resistance to drop to zero. Type I superconductors exhibit a single, sharp transition from the superconducting state to the normal state when subjected to a critical magnetic field. They do not allow partial penetration of magnetic fields; instead, they completely expel magnetic fields from their interior.

Characteristics:

• Exhibit the Meissner effect, which is the complete exclusion of magnetic fields from the superconducting material.
• Have relatively low critical magnetic fields compared to Type II superconductors.
• Typically consist of pure, elemental metals rather than alloys or compounds.

Examples: Tin (Sn), lead (Pb), mercury (Hg), and aluminum (Al) are common examples of Type I superconductors.

Correct Option Analysis:

The correct option is:

Option 2: Tin

Tin is a well-established example of a Type I superconductor. It exhibits superconductivity at a critical temperature of approximately 3.72 K and displays the characteristic sharp transition from superconducting to normal state when subjected to its critical magnetic field. Tin’s behavior aligns with the defining properties of Type I superconductors, such as the complete expulsion of magnetic fields and the abrupt transition at the critical field.

Additional Information

To further understand the analysis, let’s evaluate the other options:

Option 1: Niobium tin

Niobium tin (Nb₃Sn) is not a Type I superconductor; it is a Type II superconductor. Type II superconductors have higher critical magnetic fields and exhibit partial penetration of magnetic fields, forming vortex states. Niobium tin is widely used in applications requiring high magnetic fields, such as in particle accelerators and MRI machines.

Option 3: Niobium titanium

Niobium titanium (Nb-Ti) is another example of a Type II superconductor. It is an alloy and not a pure elemental metal, which inherently makes it unsuitable as a Type I superconductor. Niobium titanium is commonly used in industrial applications due to its excellent superconducting properties at high magnetic fields.

Option 4: Yttrium barium copper oxide

Yttrium barium copper oxide (YBCO) is a high-temperature superconductor and belongs to the family of Type II superconductors. It is a ceramic compound rather than an elemental metal and exhibits superconductivity at significantly higher critical temperatures compared to Type I superconductors. YBCO is used in various advanced applications, such as in superconducting magnets and power transmission systems.

Conclusion:

Type I superconductors are characterized by their simplicity in composition (typically elemental metals) and abrupt transition between superconducting and normal states. Tin is a classic example of a Type I superconductor, demonstrating the fundamental properties of this category. In contrast, the other options listed in the question pertain to Type II superconductors or high-temperature superconductors, which differ significantly in their behavior and applications. Understanding the distinct features of Type I and Type II superconductors is essential for correctly identifying their examples and applications.