n 1905, it was Einstein who suggested the concept of light having a dual nature; particle and wave nature. In a similar way, Louise de Broglie suggested that electron also exhibits a dual nature. Broglie derived a mathematical expression to prove the wave nature of electron along with particle nature. He gave the following relation:- ë =h/mí, where ë is the wavelength of electron, m is mass of an electron and í is the frequency.

Correct Option: A

n 1905, it was Einstein who suggested the concept of light having a dual nature; particle and wave nature. In a similar way, Louise de Broglie suggested that electron also exhibits a dual nature. Broglie derived a mathematical expression to prove the wave nature of electron along with particle nature. He gave the following relation:- ë =h/mí, where ë is the wavelength of electron, m is mass of an electron and í is the frequency.

When metals are required in a ultra pure state, the zone refining method is used. The principle-employed states that the impurities, which lower the melting point of a metal remain preferentially dissolved in the liquid phase and purer metal will emerge in the solid phase.

Correct Option: B

When metals are required in a ultra pure state, the zone refining method is used. The principle-employed states that the impurities, which lower the melting point of a metal remain preferentially dissolved in the liquid phase and purer metal will emerge in the solid phase.

In 1967, based on Einstein defining the speed of light as the most constant dimension in the universe, the International System of Units isolated two specific wave counts from an emission spectrum of caesium-133 to co-define the second and the meter. Since then, caesium has been widely used in highly accurate atomic clocks. Among alkali metals, cesium has lowest ionization energy and hence it can show photoelectric effect to the maximum extent.

Correct Option: B

In 1967, based on Einstein defining the speed of light as the most constant dimension in the universe, the International System of Units isolated two specific wave counts from an emission spectrum of caesium-133 to co-define the second and the meter. Since then, caesium has been widely used in highly accurate atomic clocks. Among alkali metals, cesium has lowest ionization energy and hence it can show photoelectric effect to the maximum extent.

Transition metals are used directly as catalysts in the anti–pollution catalytic converters in car exhausts. For example, expensive transition metals such as Platinum and rhodium are used in the catalytic converters in car exhausts to reduce the emission of carbon monoxide and nitrogen monoxide, which are converted to the non–polluting gases nitrogen and carbon dioxide. 2NO(g) + 2CO(g) ⇒ N2(g) + 2CO₂(g)

Correct Option: C

Transition metals are used directly as catalysts in the anti–pollution catalytic converters in car exhausts. For example, expensive transition metals such as Platinum and rhodium are used in the catalytic converters in car exhausts to reduce the emission of carbon monoxide and nitrogen monoxide, which are converted to the non–polluting gases nitrogen and carbon dioxide. 2NO(g) + 2CO(g) ⇒ N2(g) + 2CO₂(g)

The red, orange, yellow, green, blue and purple colors exploding in the night sky during a pyrotechnic festival are created by the use of metal salts. Barium chloride provides green colour to firework displays. Metal salts that are commonly used in firework displays include: strontium carbonate (red), calcium chloride (orange), sodium nitrate (yellow), barium chloride (green fireworks) and copper chloride (blue fireworks).

Correct Option: C

The red, orange, yellow, green, blue and purple colors exploding in the night sky during a pyrotechnic festival are created by the use of metal salts. Barium chloride provides green colour to firework displays. Metal salts that are commonly used in firework displays include: strontium carbonate (red), calcium chloride (orange), sodium nitrate (yellow), barium chloride (green fireworks) and copper chloride (blue fireworks).