Microscopy in Evidence Examina...

Microscopy in Evidence Examination

Microscopy in Evidence Examination Quiz Crafted By-

Mohit Butta

Scientific Officer

Sherlock Institute of Forensic Science India Pvt. Ltd, New Delhi

Introduction to Microscopy in Evidence Examination 

The instruments commonly used in criminal or environmental forensic investigations and analysis include scanning electron and optical microscopes. These tools are used to characterize forensic evidence like fabrics, metals, textile or glass. Microscopic imaging can also aid in identifying scratches and indents from tool marks, blood, hair classification, particle analysis, or scrutinizing residues such as sand, mud, and diatoms.

Let's look at the questions and their answer. 

Ques 1. Which part of the microscope focuses the light on an object?

a)  Body tube 

b)  Abbe’s condenser 

c)  Iris diaphragm

d)  Coarse focus

Answer- b) Abbe’s condenser 

Ques 2. For photomicrography, the position of object is

a)  Beyond 2F of convex lens

b)  At 2F of convex lens

c)  Between F and 2F of the lens

d)  Less than F of the lens

Answer- c) Between F and 2F of the lens

Ques 3. Which of the microscopes below is usually good for use on unstained specimens?

a)  Phase Contrast

b)  Bright Field

c)  Scanning Electron                                                        

d)  Transmission Electron

Answer- a) Phase Contrast

Ques 4. Which of the following is best suited to get the surface view of an object? 

a)  SEM

b)  TEM

c)  Both a and b

d)  Compound Microscope

Answer- a) SEM

Ques 5. Polarizing microscope is also referred to as 

a)  Epi Microscope

b)  Petrographic Microscope

c)  Biological Microscope

d)  Phase-contrast Microscope

Answer- b) Petrographic Microscope

Ques 6. Which microscope has found wide application for the examination of birefringent material present in soil?

a)  Comparison Microscope

b)  Stereomicroscope

c)  Fluorescent Microscope

d)  Polarising Microscope

Answer- d) Polarising Microscope

Ques 7. The numerical aperture of an objective lens is

a)  N.A. = 2 n sin θ 

b)  N.A. = n sin θ                                                        

c)  N.A. = 0.61 λ/N.A.

d)  N.A. = √0.61 λ/N. A

Answer- b) N.A. = n sin θ

Ques 8. In SEM, the incident beam is focussed by means of 

a)  Lens

b)  Mirrors                                                        

c)  Electromagnets

d)  Slits

Answer- c) Electromagnets

Ques 9 In Scanning Electron Microscope, the magnified image of a particle is formed by

a)  Primary electrons            

b)  The secondary and back-scattered electrons

c)  X-rays generated when the electron beam strikes the particle                                           

d)  All of the above

Answer- b) The secondary and back-scattered electrons

Ques 10. Which of the following is a method for preservation of specimen’s structures in scanning Electron Microscope? 

a)  Heating

b)  Immersing in wax                 

c)  Freeze-etching

d)  Under high pressure

Answer- c) Freeze-etching

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