Forensic Physics: Glass Refractive Index Measurement and SEM-EDX Fingerprinting
Published:
Questions
32
Duration
30 min
Faculty-reviewed
0
Updated
25 May 2026
About this mock
UGC-NET Forensic Science Unit VII advanced drill on forensic glass examination, covering refractive index measurement by the Becke line method and the GRIM3 hot-stage automated system (Foster and Freeman), RI population ranges (borosilicate 1.470 to 1.476, soda-lime container 1.515 to 1.520, tempered side window 1.516 to 1.520, laminated windshield 1.518 to 1.523), density gradient column analysis using bromoform and bromobenzene, LIBS under ASTM E2926, SEM-EDX elemental fingerprinting (Ca, K, Na, Mg, Fe, Ti, Sr, Zr), ICP-MS and LA-ICP-MS under ASTM E2927, match criteria (RI within ±0.0001, four-element ±2SD method), and statistical interpretation using population databases.
All questions are calibrated at hard difficulty. Distractors differ on a single parameter -- one RI value, one ASTM standard code, one spectral range, one laser wavelength, one tolerance boundary -- requiring precise recall rather than elimination. Indian forensic context includes CFSL Chandigarh glass section case protocols, the Indian automotive glass population database, and the probabilistic framework (likelihood ratio and match probability) applied in Indian courts. ASTM E1967 (automated hot stage), E2330 (Becke line), E2926 (LIBS), and E2927 (LA-ICP-MS) are each tested as distinct standards governing distinct methods.
Topics covered:
- Becke line method: direction of movement, match-point visibility criterion, oil immersion principle
- GRIM3: hot-stage silicone oil, negative dRI/dT, automated contrast-minimum detection, ±0.0001 precision
- RI numerical ranges: borosilicate vs soda-lime container vs tempered side window vs laminated windshield
- Density gradient column: bromoform-bromobenzene, iso-density equilibrium, calibration beads
- LIBS under ASTM E2926: time-gated acquisition, UV-visible atomic emission, ambient pressure advantage over SEM-EDX
- SEM-EDX elemental fingerprinting: Sr, Zr, Ti, Fe as discriminators; major-element profile for soda-lime glass
- ICP-MS and LA-ICP-MS under ASTM E2927: detection limits, solid-state ablation, 29Si internal standard
- Match criteria and statistical interpretation: RI tolerance, four-element method, CFSL and FBI database frequency
Calibrated for UGC-NET Paper II Unit VII top-decile candidates and NFSU MSc Forensic Chemistry entrance examinees. Allow 30 minutes.
Sources & references
Questions in this mock are written and verified against the following sources. Citations are recorded per question and shown in the explanation after submission.
- cited in 13 questions
Caddy, Brian (Ed.) -- Forensic Examination of Glass and Paint, Taylor and Francis
Chapter 1: Examination Strategy -- Sequential Protocol from Physical Fit to Elemental Fingerprinting
- cited in 6 questions
Koons, Robert D. and Buscaglia, JoAnn -- The Forensic Significance of Glass Composition and Refractive Index Measurements, Journal of Forensic Sciences
Section: Strontium as a Discriminating Element -- Raw Material Provenance and Concentration Range
- cited in 3 questions
ASTM E1967 -- Standard Test Method for the Automated Determination of Refractive Index of Glass Samples Using the Oil Immersion Method with a Phase Contrast Microscope and an Automated Hot Stage
Section 1: Scope -- Automated Hot Stage RI Method for Forensic Glass Comparison
- cited in 3 questions
ASTM E2926 -- Standard Guide for Forensic Analysis of Glass by Laser-Induced Breakdown Spectroscopy
Section 6: Equipment -- Spectral Collection Window and Elemental Lines for Glass Discrimination
- cited in 3 questions
ASTM E2927 -- Standard Test Method for Determination of Trace Elements in Soda-Lime Glass Samples Using Laser Ablation Inductively Coupled Plasma Mass Spectrometry
Section 8: Internal Standard -- 29Si Normalisation for Ablation Yield Correction
- cited in 2 questions
ASTM E2330 -- Standard Test Method for Determination of Refractive Index of Glass Samples Using the Becke Line Method
Section 7: Procedure -- Match Point Observation and Fragment Visibility Criterion
- cited in 1 question
SWGMAT -- Guidelines for the Forensic Analysis of Glass (Scientific Working Group for Materials Analysis)
Section 5: Elemental Comparison Criteria -- Four-Element Method, Mean ± 2SD Decision Rule
- cited in 1 question
Saferstein, Richard -- Criminalistics: An Introduction to Forensic Science, 12th Edition, Pearson
Chapter 4: Glass -- Becke Line Method, Refractive Index Matching
How our mocks are built
Questions are written and edited by the ForensicSpot team and cited from peer-reviewed forensic textbooks, official syllabi and primary case law. Each one is verified before publishing. Detailed explanations show after you submit, so the test stays a real test. See a mistake? Tell us.
Common questions
What does the Forensic Physics: Glass Refractive Index Measurement and SEM-EDX Fingerprinting mock cover?+
UGC-NET Forensic Science Unit VII advanced drill on forensic glass examination, covering refractive index measurement by the Becke line method and the GRIM3 hot-stage automated system (Foster and Freeman), RI population ranges (borosilicate 1.470 to 1.476, soda-lime container 1.515 to 1.520, tempered side window 1.516 to 1.520, laminated windshield 1.518 to 1.523), density gradient column analysis using bromoform and bromobenzene, LIBS under ASTM E2926, SEM-EDX elemental fingerprinting (Ca, K, N
How many questions and how long is the test?+
32 multiple-choice questions, 30 minutes total. Difficulty: hard. Tier: Premium.
Who is this mock for?+
Forensic science students and aspirants who want timed, exam-style practice with explanations and verified source citations on Forensic Physics, NET. Useful for postgraduate entrance preparation and for BSc / MSc forensic students testing their recall under time.
Are the questions reviewed?+
Each question carries a verified source citation. Faculty review for individual questions is in progress.
Do I need an account to take this mock?+
Yes, a free ForensicSpot account is required to start a timed attempt — this lets you save progress, see per-question explanations after submission, and track your topic-level performance over time.