Tentafrågor 2021 flervals frågor

Question 1

According to oxygen consumption calorimetry, for each kilogram of oxygen consumed, how much amount of energy is released for most materials?

a. 13100 MJ
b. 13100 kJ
c. 13.1 kJ
d. 13.1 MJ

Answer 1

b. 13100 kJ
d. 13.1 MJ

Question 2

For pool fires, which of the following fuels have no diameter dependence?

a. Coal
b. Methane
c. Magnesium hydroxide
d. C2H5OH

Answer 2

b. Methane
d. C2H5OH

Question 3

Axisymmetric fire plume can be divided into three regions. In which region, the velocity is constant?

a. Far field zone
b. Buoyant zone
c. Intermittent zone
d. Continuous zone

Answer 3

c. Intermittent zone

Question 4

In general, most of the Heskestad plume equations are only valid above the mean flame height. However, which parameter can be determined using Heskestad equation below the mean flame height?

a. Radius of plume
b. Mass flow rate of plume
c. Velocity of plume
d. Temperature difference

Answer 4

b. Mass flow rate of plume

Question 5

In case of large fires, the temperature in the continuous region can be very high (ca. 800 -1200 C). What is one of the main reasons for this?

a. Soot blockage prevents losses in the form of radiation
b. High plume velocity in the region.
c. Very high temperature difference between ambient air and flame.
d. No conductive or convective heat transfer.

Answer 5

A. Soot blockage prevents losses in the form of radiation

Question 6

If a source of fire is not circular, which set of equations are the best bet to determine its plume mass flow rate?

a. Ideal plume equations
b. Heskestad plume equations
c. Zukoski plume equations
d. None of the above

Answer 6

d. None of the above

Question 7

The Bernoulli equation is only valid for fluid flow that is:

a. Compressible and isothermal
b. Incompressible and isothermal
c. Isothermal and friction-free
d. Incompressible and no heat loses to the surrounding

Answer 7

b. Incompressible and isothermal
c. Isothermal and frictions-free
d. Incompressible and no heat loses to the surrounding

Question 8

In the decay stage of room fire, the fire can become:

a. Ventilation-controlled
b. Fuel- controlled
c. Extingguished
d. Fully-developed

Answer 8

b. Fuel- controlled
c. Extingguished

Question 9

The ventilation factor is directly proportional to the mass flow rate in through a vent in a room during the:

a. Growth stage
b. Fully-developed fire stage
c. Post-flashover stage
d. During flashover

Answer 9

c. Post-flashover stage

Question 10

What is one of the shortcomings of the ISO-834 fire curve?

a. Temperature keeps on rising
b. Considers that the fire will eventually decline
c. Ignores flashover might happen
d. Considers fuel types

Answer 10

a. Temperature keeps on rising