Read
the passage carefully and answer the following questions (1-5)-
A convict & a
suspect in a burglary offence setup a small fire in his hut to scare the
raiding police party, which had come to arrest him at late hours of night. The fire
could not be controlled & his pregnant wife received serious burn injuries
& later died in hospital. To cover up his misdeed, he put the blame on the
raiding police party for setting up fire to his hut by throwing petrol from the
vehicle from outside his hut. In the course of investigation forensic experts
collected burnt residue of cloth, which was used to initiate fire & &
the sample of earth underneath was collected along with the bottle of kerosene
available in the hut. Likewise sample of soil & a gunny bag lying outside
the house was collected. All the samples were examined in lab by GC. Samples collected
from inside the hut revealed presence of residues of kerosene, whereas no trace
of petrol was found both inside & outside the hut. The allegation on the
police was cleared & suspected burglar was charged of homicidal offence.
1.
Assertion
(A): Heavy black smoke is characteristic of burning of most liquid hydrocarbons.
Reason (R): Burning
of oil, petrol, tar, paint, & similar organic material produce a black
carbonaceous smoke.
a) Both
A and R are correct and R is the correct explanation of A
b) Both
A and R are correct but R is not the correct explanation of A
c) A
is correct but R is not correct
d)
A is not correct but R is correct.
ANSWER-A
2.
Assertion
(A): GC can be useful for positive identification of volatile flammable
material.
Reason (R): Petrol & kerosene are volatile
flammable material.
a) Both
A and R are correct and R is the correct explanation of A
b) Both
A and R are correct but R is not the correct explanation of A
c) A
is correct but R is not correct
d)
A is not correct but R is correct.
ANSWER-B
EXPLANATION
Substance's volatility is closely linked to its vapor
pressure, or the pressure at which its gaseous phase is in equilibrium with its
liquid phase.
3.
Wallace
Rule of nines is related to which among the following evidence-
A.
Dead body
B.
Skeletal
remains
C.
Burnt body
D.
All of
these
ANSWER-C
EXPLANATION
4. Match the following-
A. A-II, B-I, C-IV, D-III
B. A-III, B-I, C-IV, D-II
C. A-III, B-IV, C-II, D-I
D. A-IV, B-III, C-I, D-II
ANSWER-B
EXPLANATION
5. Match the following-
A. A-II,
B-I, C-IV, D-III
B. A-III,
B-I, C-IV, D-II
C. A-III,
B-IV, C-II, D-I
D. A-IV,
B-III, C-I, D-II
ANSWER-D
EXPLANATION
1. Incandescence:- Emission of electromagnetic radiation from a hot body
as a result of its high temperature. It is light produced from heat. Heat
causes a substance to become hot and glow, initially emitting infrared, then
red, orange, yellow, and white light as it becomes increasingly hotter.
2. Luminescence:- Also known as cold light because it can occur at
room temperature and cooler temperatures.. It is light produced using
energy sources other than heat.
3. Smouldering:- a form of flame
less combustion, occurs at the surface of the material in cellulosic
substances that can form a solid char. It is characterized by externally localized burning & production of thick tarry smoke. The presence
of a smouldering fire is characterized by extremely localized burning
and the production of thick, tarry smoke. The surface temperature can be linked
to the color of the smouldering. For example, dark red surfaces suggest a
temperature of 500-600oC, whereas a white surface indicates
temperatures in excess of 1400oC.
4. Ignition:- act of causing something to start burning. It is induced
by the addition of heat to a fuel in air, which can be caused by various
sources such as exothermic chemical reactions, friction, solar radiation and
electricity.
ADDITIONAL POINT:-
Solid and liquid materials(pyrotechnic compounds or volatile
flammables) are not actually combust instead it is the process of heating
caused them to produce vapours that can burn. It is known as pyrolysis. Due to
this pyrolysis products will be formed, flammable and volatile substances of
low molecular weight caused through the decomposition of materials by fire.
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