Magnesite refractories have low resistance to attack by basic slag. abrasion. di

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Question
Magnesite refractories have low resistance to
Options
A. attack by basic slag.
B. abrasion.
C. disintegration on sudden change of temperature.
D. both (b) and (c).

Correct Answer

both (b) and (c).

More questions

1. In the reaction, Ca + 2H₂O = Ca(OH)₂ + H₂ ; what volume (c.c.) of hydrogen at STP would be liberated, when 8 gm of calcium reacts with excess water? (atomic weight of calcium = 40)
Options
A. 4480
B. 2240
C. 1120
D. 0.4

2. The detrimental effect on organism and water quality with temperature rise of aquatic system is the reduction of __________ of water.
Options
A. dissolved oxygen content
B. biological oxygen demand
C. vapor pressure
D. all (a), (b) and (c)

3. Choose the correct statement regarding thermal cracking.
Options
A. Moderate changes in operating temperature does not change the depth of cracking.
B. Increased residence time results in the decreased severity of cracking.
C. At low pressure, the yield of lighter hydrocarbons are more.
D. Greater depth of cracking gives lower octane number gasoline.

5. The heating capacity of continuous reheating furnace depends upon the
Options
A. hearth area and furnace temperature.
B. emissivity of the stock.
C. ratio of wall surface to stock surface.
D. all (a), (b) and (c).

8. Water is entering a storage tank at a temperature T₀ and flow rate Q₀ and leaving at a flow rate Q and temperature T. There are negligible heat losses in the tank. The area of cross-section of the tank is A₀. The model that describes the dynamic variation of temperature of water in the tank with time is given as :
Options
A. Q₀(T₀ - T) = A_c .
B. Q₀T₀ - QT = A_c .
C. Q(T₀ - T) = A_c .
D. Q(T₀ - T) = A_c .

9. An electric furnace producing heat by means of an electric arc struck between each of three electrodes and the charge is called __________ furnace.
Options
A. resistance
B. arc
C. low frequency induction
D. none of these

10. Pick out the wrong statement.
Options
A. Aromatics have higher specific gravity than paraffins,
B. Gross calorific value (GCV) of petrofuels is equal to (12400 - 2100 ?²) where, ? is the specific gravity of the fuel at 15.5�C.
C. Heavier petrofuels have higher GCV on weight basis (i.e., Kcal/kg) but lower GCV on volume basis (i.e., Kcal/litre).
D. Higher specific gravity of petrofuels means higher C/H ratio.

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