Read the following paragraph and answer the questions given below it:
The resistance of a metal falls when cooled below room temperature. Many scientists believed that the value of the resistance would become constant at some very low temperature, allowing the current to flow with little or no resistance. H. K. Onnes successfully liquefied helium in 1908 by cooling it to about 4 K. In 1911, while investigating the electrical property of very pure mercury. Onnes discovered that at a temperature of 4.2 kelvin, its resistance practically vanished. This new state, on account of its extraordinary property, is now called the superconducting state and the phenomenon is called superconductivity. A superconductor, below a certain critical temperature, offers almost zero resistance to a flow of current through it. Onnes also discovered that a superconductor exhibits persistent current: once set up, the current continues to flow for a very long time without an electric potential difference driving it and without significant loss. Superconductivity is used in many diverse areas, such as magnetically levitated trains, transmission of electricity, increasing speed of computers, in MRI (magnetic resonance imaging).
What is a superconductor?

Read the following paragraph and answer the questions given below it: The resistance of a metal falls when cooled below room temperature. Many scientists believed that the value of the resistance would become constant at some very low temperature, allowing the current to flow with little or no resistance. H. K. Onnes successfully liquefied helium in 1908 by cooling it to about 4 K. In 1911, while investigating the electrical property of very pure mercury. Onnes discovered that at a temperature of 4.2 kelvin, its resistance practically vanished. This new state, on account of its extraordinary property, is now called the superconducting state and the phenomenon is called superconductivity. A superconductor, below a certain critical temperature, offers almost zero resistance to a flow of current through it. Onnes also discovered that a superconductor exhibits persistent current: once set up, the current continues to flow for a very long time without an electric potential difference driving it and without significant loss. Superconductivity is used in many diverse areas, such as magnetically levitated trains, transmission of electricity, increasing speed of computers, in MRI (magnetic resonance imaging). At what temperature does the resistance of very pure mercury become almost zero?

Read the following paragraph and answer the questions given below it: The resistance of a metal falls when cooled below room temperature. Many scientists believed that the value of the resistance would become constant at some very low temperature, allowing the current to flow with little or no resistance. H. K. Onnes successfully liquefied helium in 1908 by cooling it to about 4 K. In 1911, while investigating the electrical property of very pure mercury. Onnes discovered that at a temperature of 4.2 kelvin, its resistance practically vanished. This new state, on account of its extraordinary property, is now called the superconducting state and the phenomenon is called superconductivity. A superconductor, below a certain critical temperature, offers almost zero resistance to a flow of current through it. Onnes also discovered that a superconductor exhibits persistent current: once set up, the current continues to flow for a very long time without an electric potential difference driving it and without significant loss. Superconductivity is used in many diverse areas, such as magnetically levitated trains, transmission of electricity, increasing speed of computers, in MRI (magnetic resonance imaging). Name the scientist who discovered superconductivity.

Read the following paragraph and answer the questions given below it: The resistance of a metal falls when cooled below room temperature. Many scientists believed that the value of the resistance would become constant at some very low temperature, allowing the current to flow with little or no resistance. H. K. Onnes successfully liquefied helium in 1908 by cooling it to about 4 K. In 1911, while investigating the electrical property of very pure mercury. Onnes discovered that at a temperature of 4.2 kelvin, its resistance practically vanished. This new state, on account of its extraordinary property, is now called the superconducting state and the phenomenon is called superconductivity. A superconductor, below a certain critical temperature, offers almost zero resistance to a flow of current through it. Onnes also discovered that a superconductor exhibits persistent current: once set up, the current continues to flow for a very long time without an electric potential difference driving it and without significant loss. Superconductivity is used in many diverse areas, such as magnetically levitated trains, transmission of electricity, increasing speed of computers, in MRI (magnetic resonance imaging). What is special about a superconductor?

Read the following paragraph and answer the questions given below it: The resistance of a metal falls when cooled below room temperature. Many scientists believed that the value of the resistance would become constant at some very low temperature, allowing the current to flow with little or no resistance. H. K. Onnes successfully liquefied helium in 1908 by cooling it to about 4 K. In 1911, while investigating the electrical property of very pure mercury. Onnes discovered that at a temperature of 4.2 kelvin, its resistance practically vanished. This new state, on account of its extraordinary property, is now called the superconducting state and the phenomenon is called superconductivity. A superconductor, below a certain critical temperature, offers almost zero resistance to a flow of current through it. Onnes also discovered that a superconductor exhibits persistent current: once set up, the current continues to flow for a very long time without an electric potential difference driving it and without significant loss. Superconductivity is used in many diverse areas, such as magnetically levitated trains, transmission of electricity, increasing speed of computers, in MRI (magnetic resonance imaging). Name any two applications of super-conductivity.

Define the temperature coefficient of resistance of material.

Answer the following question in one sentence : Name two non-metals which are in solid state at room temperature.

Explain the effect of temperature on resistance?

Answer the following question in one sentence : name a non-metal which is an liquid state at room temperature.

Answer the following question in one sentence : Name two non-metals which are gaseous state at room temperature.