Question

8. A bare PZT crystal placed inside a drop-shock tester is accelerated through 10g. The voltage output from the crystal during this process

a. increases b. remains a constant non-zero value c. is zero d. cannot be determined

Reason:

9. When a liquid comes in contact with a hydrophobic microchannel surface, the surface tension of the liquid

a. Increases b. Decreases c. Remains the same d. Varies randomly

Reason:

10. PDMS based microfluidics is sometimes affected by ‘leaching’, which basically is uncrosslinked oligomers from the base material “leaking” into the microfluidic channel. Which of these could be a contributor to this problem?

a. Uneven mixing of pre-polymer and binder b. Incompletely cured pre-polymer and binder c. Ratio of Pre-polymer- Binder d. Only a & b

Reason:

Answer 1

8. The voltage output of the PZT crystal place inside a drop-shock tester will increase when it is accelerated through 10g . With the acceleartion, the voltage produced also increases in a drop-shock tester. Hence, the correct answer is option 'a'.

9. The surface tension of the liquid decrease when it comes in contact with a hydrophobic mircochannel surface. The adhesive forces of the liquid will keep the molecules together and ot will flow easily on the hydrophobic surface. The low surface tension is responsible for such easy flow. Hence, the correct answer is option 'b'.

10. The incompletely cured pre-polymer and binders cause the leaking of the uncross-linked oligomers from the base material. Hence, the correct answer is option 'b'.