1798. Which of the following alloy steels is the most suitable for making gun barrels and projectiles?
Tungsten steel
Molybdenum steel
Nickel-chrome steel
Cobalt steel
✅ The correct answer is option C.
1801. White cast iron is not
Malleable
Whitish in color
Brittle
Strong and hard
✅ The correct answer is option A.
1804. Polythene (low or high density) containers are not corroded by
Sulphuric acid (10%) at room temperature
Nitric acid (95%) at room temperature
Sulphur trioxide at 60°C
Any of these
✅ The correct answer is option A.
1807. Addition of 2% nickel in steel makes it suitable for making
Electronic valves
Boiler plates, rivets etc
Turbine blades
Connecting rod
✅ The correct answer is option B.
1813. Hardest materials so far found is
Diamond
Graphite
Carborundum
Pumice stone
✅ The correct answer is option A.
1816. ‘Age hardening’ of duralumin is due to
Copper
Magnesium
Both A & B
Neither A nor B
✅ The correct answer is option C.
1819. Heavy duty bearings are usually made of
White metal
Phosphorous bronze
Monel
Zinc
✅ The correct answer is option A.
1821. Babbit metal used for making bearings should have
High-co-efficient of friction between journal and bearing
Ability to retain lubricant on its surface
Low co-efficient of friction between journal and bearing
Both B & C
✅ The correct answer is option A.
1823. The ‘bomb’ in the bomb calorimeter is made of
Molybdenum stainless steel
Mild steel
High silicon iron (14% Si)
Copper
✅ The correct answer is option A.