3416. The velocity of thermal (slow) neutrons triggering nuclear fission reaction (having energy equal to 0.025 eV) is about __________ metres/second.
1100
2200
3300
4400
✅ The correct answer is option B.
3421. The new nucleus formed after β-decay of a radioactive element has
less atomic number
less atomic weight
more atomic number
more atomic weight
✅ The correct answer is option A.
3425. The amount of a radioactive material (having a half life of 100 years) remaining after 400 years will be __________ of its original weight.
1-Feb
1-Apr
1-Aug
Jan-16
✅ The correct answer is option D.
3430. The main ore of uranium is
pitchblende
monazite sand
cassiterite
chalcopyrite
✅ The correct answer is option A.
3436. Uranium Corporation of India Limited (UCIL) engaged in the mining & concentration of uranium ore is located at
Alwaye (in Kerala)
Jadugoda (in Jharkhand)
Kalpakkam (in Tamilnadu)
Gopalpur coast (in Orissa)
✅ The correct answer is option B.
3402. With increase in moisture content of coal, its
Calorific value increases sometimes
Bulk density always decreases
Clinkering tendency during combustion increases
None of these
✅ The correct answer is option D.
3403. Coal tar fuel – 200 (CTF 200) is a mixture of
Pitch and creosote oil
Light oil and pitch
Anthracene and crecosote oil
Solar oil and pitch
✅ The correct answer is option A.
3370. Pure carbon is completely burnt in oxygen. The flue gas analysis is 70%CO₂, 20%CO and 10%O₂. The percent excess oxygen used is
20
12.5
0
10
✅ The correct answer is option C.
3381. Dry air required to burn 1 kg of carbon completely may be around __________ kg.
11
2
20
38
✅ The correct answer is option A.
3385. Efficient burning of anthracite coal requires
Low preheat of air
Fine grinding
High excess air
All of the above
✅ The correct answer is option B.