Nano Module-1

Typical precursor used in sol-gel are ____________

• Metal oxides
  

• Metal dioxides

• Metal alkoxides

• Metal fluorides

Which gas serves as buffer gas in Laser ablation?

• Nitrogen
  

• Oxygen

• Helium

• Neon

Answer explanation

Laser ablation has been extensively used for the preparation of nanoparticles. In the device, there is a pulsed flow of Helium gas. It serves as a buffer gas in which clusters of the target material form, thermalize.

In ball milling method Tungsten Carbide and Precursor are taken in the ratio of ___________

• 3:1

• 2:1

• 1:1

• 3:1

In laser ablation ____ range is preferred

• UV

• IR

• VIS

Nano materials shows which of the below properties/property due to increase in the surface to volume ratio

• large fraction of surface atoms

• high surface energy

• spatial confinement

• reduced imperfections

• All the above

The enhancement in mechanical strength of nanomaterial say Copper compared to bulk is/are due to ________

• reduced impurity precipitates.

   

• reduced dislocations

• reduced micro-twins

• All the above

For milling operations, what kind of environment is preferred?

• Acidic

• Basic

• Inert

____________ is used in sputtering method.

• Laser

• Partially ionized gas

• Tungsten carbide

• Precipitating agent