281. Oxygen cylinders used for autogenous (cutting/welding) purposes are ___________________?
A. Seamless & made of steel
B. Heat treated before use
C. Made by sand casting
D. Welded steel cylinders

282. Heating of ferromagnetic materials to a temperature above Curie temperature makes it ________________________?
A. Insulator for heat & electricity transmission
B. Ferritic
C. Behave like paramagnetic materials
D. Superconductor

283. Which of the, following is not associated with the functioning of a petrol engine ?
A. Compression ignition system
B. Spark plug
C. Carburettor
D. Otto cycle

284. Principal alloying elements of cast tool alloys which have very high wear resistance & high temperature strength are ?
A. Cobalt, chromium & tungsten
B. Cobalt, chromium & nickel
C. Molybdenum, tungsten & chromium
D. Cobalt, zirconium & molybdenum

285. Breakeven point represents the condition, when the company runs under no profit no loss condition. In break even analysis, total cost comprises of fixed cost________________?
A. Only
B. Plus variable cost
C. Plus overhead cost
D. Plus selling expenses

286. Property responsible for the talcum powder to cling to the skin is the__________________?
A. Capillary action
B. Adhesion
C. Cohesion
D. Surface tension

287. During decarburising of a plain carbon steel, the thickness of ferrite layer growth is proportional to____________________?
A. Time
B. Square root of time
C. Square of time
D. Cube of time

288. Percentage of differential pressure lost in a Venturimeter with a tapering of 15° may be about___________________?
A. 1
B. 10
C. 25
D. 50

289. ____________________ flux is used for the extraction of metal from its self fluxing ores?
A. No
B. Acid
C. Basic
D. Neutral

290. Uniform ramming of sand in green sand moulding process leads to____________________?
A. Reduced chance of gas porosity
B. Greater dimensional stability of the casting
C. Uniform flow of molten metal into the mold cavity
D. Less sand expansion type of casting defect

NOTE
IF YOU THINK ANY OF THE MCQ ABOVE IS WRONG.
PLEASE COMMENT WITH CORRECT ANSWER AND ITS DETAIL EXPLANATION IN COMMENT BOX.
THANK YOU