Question 1: Which of the following properties is most commonly used to compare glass fragments in forensic analysis?
- A. Color
- B. Density
- C. Refractive index
- D. Thickness
Answer
Answer: C. Refractive index
Explanation: The refractive index (RI) is one of the most commonly used properties to compare glass fragments in forensic analysis. It measures how light bends as it passes through the glass and is highly specific to the composition of the glass. Density and color are also useful, but RI provides more precise discrimination between glass samples.
Question 2: What is the primary technique used to measure the refractive index of glass fragments?
- A. X-ray diffraction (XRD)
- B. Scanning electron microscopy (SEM)
- C. Immersion method
- D. Fourier-transform infrared spectroscopy (FTIR)
Answer
Answer: C. Immersion method
Explanation: The immersion method is the primary technique used to measure the refractive index of glass fragments. It involves immersing the glass in liquids of known refractive indices and observing the Becke line (a bright halo around the glass) to determine the match point.
Question 3: Which of the following elements is typically present in high concentrations in tempered glass?
- A. Sodium
- B. Potassium
- C. Calcium
- D. Magnesium
Answer
Answer: B. Potassium
Explanation: Tempered glass, also known as safety glass, often contains high concentrations of potassium. This is due to the ion exchange process used during tempering, where sodium ions in the glass are replaced with larger potassium ions to create surface compression.
Question 4: What is the term for the stress-induced fracture pattern observed in glass fragments?
- A. Conchoidal fractures
- B. Radial fractures
- C. Hackle marks
- D. Wallner lines
Answer
Answer: A. Conchoidal fractures
Explanation: Conchoidal fractures are the stress-induced fracture patterns commonly observed in glass fragments. They are characterized by smooth, curved surfaces resembling the interior of a seashell and are a key feature in forensic glass analysis.
Question 5: Which of the following techniques is used to analyze the elemental composition of glass fragments?
- A. Refractive index measurement
- B. Scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS)
- C. Immersion method
- D. Ultraviolet-visible spectroscopy (UV-Vis)
Answer
Answer: B. Scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS)
Explanation: SEM-EDS is a technique used to analyze the elemental composition of glass fragments. It combines scanning electron microscopy with energy-dispersive X-ray spectroscopy to identify and quantify the elements present in the glass.
Question 6: What is the primary purpose of the Becke line in glass analysis?
- A. To measure the thickness of the glass
- B. To determine the refractive index of the glass
- C. To identify the color of the glass
- D. To analyze the fracture patterns
Answer
Answer: B. To determine the refractive index of the glass
Explanation: The Becke line is a bright halo that appears around the edges of a glass fragment when it is immersed in a liquid. It is used to determine the refractive index of the glass by observing the direction of the line’s movement as the focus of the microscope is adjusted.
Question 7: Which of the following types of glass is most likely to exhibit a high refractive index?
- A. Soda-lime glass
- B. Borosilicate glass
- C. Lead glass
- D. Tempered glass
Answer
Answer: C. Lead glass
Explanation: Lead glass, also known as crystal glass, is most likely to exhibit a high refractive index due to the presence of lead oxide in its composition. This gives it a higher density and greater light-bending ability compared to soda-lime or borosilicate glass.
Question 8: What is the term for the small, curved ridges found on the edges of broken glass fragments?
- A. Wallner lines
- B. Hackle marks
- C. Conchoidal fractures
- D. Radial fractures
Answer
Answer: B. Hackle marks
Explanation: Hackle marks are small, curved ridges found on the edges of broken glass fragments. They are formed due to the propagation of fractures and can provide information about the direction of the breaking force.
Question 9: Which of the following is a characteristic of borosilicate glass?
- A. High thermal expansion
- B. Low resistance to thermal shock
- C. High boron oxide content
- D. High lead content
Answer
Answer: C. High boron oxide content
Explanation: Borosilicate glass is characterized by its high boron oxide content, which gives it low thermal expansion and high resistance to thermal shock. It is commonly used in laboratory glassware and cookware.
Question 10: Which of the following techniques is used to determine the sequence of impacts in a broken glass pane?
- A. Refractive index measurement
- B. Fracture pattern analysis
- C. Elemental analysis
- D. Density measurement
Answer
Answer: B. Fracture pattern analysis
Explanation: Fracture pattern analysis is used to determine the sequence of impacts in a broken glass pane. Radial and concentric fractures, as well as the termination points of fractures, can provide clues about the order in which the glass was struck.
Question 1: Which of the following properties is most commonly used to compare glass fragments in forensic analysis?
- A. Color
- B. Density
- C. Refractive index
- D. Thickness
Answer
Answer: C. Refractive index
Explanation: The refractive index (RI) is one of the most commonly used properties to compare glass fragments in forensic analysis. It measures how light bends as it passes through the glass and is highly specific to the composition of the glass. Density and color are also useful, but RI provides more precise discrimination between glass samples.
Question 2: What is the primary technique used to measure the refractive index of glass fragments?
- A. X-ray diffraction (XRD)
- B. Scanning electron microscopy (SEM)
- C. Immersion method
- D. Fourier-transform infrared spectroscopy (FTIR)
Answer
Answer: C. Immersion method
Explanation: The immersion method is the primary technique used to measure the refractive index of glass fragments. It involves immersing the glass in liquids of known refractive indices and observing the Becke line (a bright halo around the glass) to determine the match point.
Question 3: Which of the following elements is typically present in high concentrations in tempered glass?
- A. Sodium
- B. Potassium
- C. Calcium
- D. Magnesium
Answer
Answer: B. Potassium
Explanation: Tempered glass, also known as safety glass, often contains high concentrations of potassium. This is due to the ion exchange process used during tempering, where sodium ions in the glass are replaced with larger potassium ions to create surface compression.
Question 4: What is the term for the stress-induced fracture pattern observed in glass fragments?
- A. Conchoidal fractures
- B. Radial fractures
- C. Hackle marks
- D. Wallner lines
Answer
Answer: A. Conchoidal fractures
Explanation: Conchoidal fractures are the stress-induced fracture patterns commonly observed in glass fragments. They are characterized by smooth, curved surfaces resembling the interior of a seashell and are a key feature in forensic glass analysis.
Question 5: Which of the following techniques is used to analyze the elemental composition of glass fragments?
- A. Refractive index measurement
- B. Scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS)
- C. Immersion method
- D. Ultraviolet-visible spectroscopy (UV-Vis)
Answer
Answer: B. Scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS)
Explanation: SEM-EDS is a technique used to analyze the elemental composition of glass fragments. It combines scanning electron microscopy with energy-dispersive X-ray spectroscopy to identify and quantify the elements present in the glass.
Question 6: What is the primary purpose of the Becke line in glass analysis?
- A. To measure the thickness of the glass
- B. To determine the refractive index of the glass
- C. To identify the color of the glass
- D. To analyze the fracture patterns
Answer
Answer: B. To determine the refractive index of the glass
Explanation: The Becke line is a bright halo that appears around the edges of a glass fragment when it is immersed in a liquid. It is used to determine the refractive index of the glass by observing the direction of the line’s movement as the focus of the microscope is adjusted.
Question 7: Which of the following types of glass is most likely to exhibit a high refractive index?
- A. Soda-lime glass
- B. Borosilicate glass
- C. Lead glass
- D. Tempered glass
Answer
Answer: C. Lead glass
Explanation: Lead glass, also known as crystal glass, is most likely to exhibit a high refractive index due to the presence of lead oxide in its composition. This gives it a higher density and greater light-bending ability compared to soda-lime or borosilicate glass.
Question 8: What is the term for the small, curved ridges found on the edges of broken glass fragments?
- A. Wallner lines
- B. Hackle marks
- C. Conchoidal fractures
- D. Radial fractures
Answer
Answer: B. Hackle marks
Explanation: Hackle marks are small, curved ridges found on the edges of broken glass fragments. They are formed due to the propagation of fractures and can provide information about the direction of the breaking force.
Question 9: Which of the following is a characteristic of borosilicate glass?
- A. High thermal expansion
- B. Low resistance to thermal shock
- C. High boron oxide content
- D. High lead content
Answer
Answer: C. High boron oxide content
Explanation: Borosilicate glass is characterized by its high boron oxide content, which gives it low thermal expansion and high resistance to thermal shock. It is commonly used in laboratory glassware and cookware.
Question 10: Which of the following techniques is used to determine the sequence of impacts in a broken glass pane?
- A. Refractive index measurement
- B. Fracture pattern analysis
- C. Elemental analysis
- D. Density measurement
Answer
Answer: B. Fracture pattern analysis
Explanation: Fracture pattern analysis is used to determine the sequence of impacts in a broken glass pane. Radial and concentric fractures, as well as the termination points of fractures, can provide clues about the order in which the glass was struck.
Question 1: Which of the following properties is most commonly used to compare glass fragments in forensic analysis?
- A. Color
- B. Density
- C. Refractive index
- D. Thickness
Answer
Answer: C. Refractive index
Explanation: The refractive index (RI) is one of the most commonly used properties to compare glass fragments in forensic analysis. It measures how light bends as it passes through the glass and is highly specific to the composition of the glass. Density and color are also useful, but RI provides more precise discrimination between glass samples.
Question 2: What is the primary technique used to measure the refractive index of glass fragments?
- A. X-ray diffraction (XRD)
- B. Scanning electron microscopy (SEM)
- C. Immersion method
- D. Fourier-transform infrared spectroscopy (FTIR)
Answer
Answer: C. Immersion method
Explanation: The immersion method is the primary technique used to measure the refractive index of glass fragments. It involves immersing the glass in liquids of known refractive indices and observing the Becke line (a bright halo around the glass) to determine the match point.
Question 3: Which of the following elements is typically present in high concentrations in tempered glass?
- A. Sodium
- B. Potassium
- C. Calcium
- D. Magnesium
Answer
Answer: B. Potassium
Explanation: Tempered glass, also known as safety glass, often contains high concentrations of potassium. This is due to the ion exchange process used during tempering, where sodium ions in the glass are replaced with larger potassium ions to create surface compression.
Question 4: What is the term for the stress-induced fracture pattern observed in glass fragments?
- A. Conchoidal fractures
- B. Radial fractures
- C. Hackle marks
- D. Wallner lines
Answer
Answer: A. Conchoidal fractures
Explanation: Conchoidal fractures are the stress-induced fracture patterns commonly observed in glass fragments. They are characterized by smooth, curved surfaces resembling the interior of a seashell and are a key feature in forensic glass analysis.
Question 5: Which of the following techniques is used to analyze the elemental composition of glass fragments?
- A. Refractive index measurement
- B. Scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS)
- C. Immersion method
- D. Ultraviolet-visible spectroscopy (UV-Vis)
Answer
Answer: B. Scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS)
Explanation: SEM-EDS is a technique used to analyze the elemental composition of glass fragments. It combines scanning electron microscopy with energy-dispersive X-ray spectroscopy to identify and quantify the elements present in the glass.
Question 6: What is the primary purpose of the Becke line in glass analysis?
- A. To measure the thickness of the glass
- B. To determine the refractive index of the glass
- C. To identify the color of the glass
- D. To analyze the fracture patterns
Answer
Answer: B. To determine the refractive index of the glass
Explanation: The Becke line is a bright halo that appears around the edges of a glass fragment when it is immersed in a liquid. It is used to determine the refractive index of the glass by observing the direction of the line’s movement as the focus of the microscope is adjusted.
Question 7: Which of the following types of glass is most likely to exhibit a high refractive index?
- A. Soda-lime glass
- B. Borosilicate glass
- C. Lead glass
- D. Tempered glass
Answer
Answer: C. Lead glass
Explanation: Lead glass, also known as crystal glass, is most likely to exhibit a high refractive index due to the presence of lead oxide in its composition. This gives it a higher density and greater light-bending ability compared to soda-lime or borosilicate glass.
Question 8: What is the term for the small, curved ridges found on the edges of broken glass fragments?
- A. Wallner lines
- B. Hackle marks
- C. Conchoidal fractures
- D. Radial fractures
Answer
Answer: B. Hackle marks
Explanation: Hackle marks are small, curved ridges found on the edges of broken glass fragments. They are formed due to the propagation of fractures and can provide information about the direction of the breaking force.
Question 9: Which of the following is a characteristic of borosilicate glass?
- A. High thermal expansion
- B. Low resistance to thermal shock
- C. High boron oxide content
- D. High lead content
Answer
Answer: C. High boron oxide content
Explanation: Borosilicate glass is characterized by its high boron oxide content, which gives it low thermal expansion and high resistance to thermal shock. It is commonly used in laboratory glassware and cookware.
Question 10: Which of the following techniques is used to determine the sequence of impacts in a broken glass pane?
- A. Refractive index measurement
- B. Fracture pattern analysis
- C. Elemental analysis
- D. Density measurement
Answer
Answer: B. Fracture pattern analysis
Explanation: Fracture pattern analysis is used to determine the sequence of impacts in a broken glass pane. Radial and concentric fractures, as well as the termination points of fractures, can provide clues about the order in which the glass was struck.