FILL IN THE BLANKS
1. The movement of the cantilever, when it "feels" the sample, is tracked using ______ and ________.
2. Constant height mode is useful for atomically _________ sample.
3. Scanning tunnelling microscopy should be performed at _____ temperatures for good imaging.
4. ________ wire is used as a probe for STM.
5. Difference in _________ is used for compositional mapping in LFM.
TRUE AND FALSE
1. Only metallic samples can be characterised using STM.
2. MFM utilizes the magnetic force between sample and tip for imaging.
LONG TYPE QUESTIONS
1. Why are four quadrants present in a photodetector?
2. Explain non-contact mode imaging in AFM?
3. Explain the working principle of STM?