PART III Truel False questions 33 points3 points each T F Na

PART III: Truel False questions (33 points-3 points each) (T F) Nanostructured materials exhibit different optical, electrical, chemical and biological properties due to nanosize. (T F-In bottom-up nanofabrication, a nanostructured pattern is made in a larger size and minimize to nanoscale at a later stage. (T F) Vacuum pumps are operational only in the viscous flow. (T F) In STM (Scanning Tunneling Microscopy), the tunneling current flows across the small gap that separates the tip from the sample. (T F) A (TEM) Transmission Electron Microscope is analogous to a slide projector. (T F-Mean-free path becomes smaller as the pressure goes down. (T F) The resistance of Carbon Nanotubes is dependent of the length of the wire (T F) A good optical microscope can have any resolution between 1nm to 10nm. (T F) One bar is equal to one atmospheric pressure (T F) In Scanning Tunneling Microscopy (STM), the sample surface has to be conductive. (T F) In Transmission Electron Microscopy (TEM), the sample surface has to be nonconductive.

Solution

1. nanostructured materials ... - TRUE ( length =of nanosize typically 1–10 nanometer )

2. In bottom up nano fabriction - FALSE ( It is buildup in the atom size 1 nm NOT in large size)

3. viscous flow in vacuum pump towards low pressure - TRUE

4. In STM , tunneling current flows - TRUE (The result of tunneling current is applied voltage, a function of tip position, and the LDOS of the sample ) local density of states (LDOS)

5.TEM IS analogous in many ways to the conventional (compound) light microscope - TRUE

6. MFP BECOMES SMALLER in ...- TRUE ( In viscous flow mass moves in to low pressure - It refers pressure goes down)

7. Resistance of carbon nanotubes is ... FALSE ( It depends on diameter )

8. Optical microscope resolution . 1mm to 100nm - FALSE (only electron microscope can do that)

9 . one bar equal to --- TRUE ( 0.986923 Atmosphere)

10. STM surface conductive - TRUE (a bias applied between the two can allow electrons to tunnel through the vacuum between them. )

11 . TEM surface non conductive is to prevent charge build-up at the sample surface - TRUE