BharatNotes Fusion
nounUsage in a UPSC answer
The new social-welfare architecture represents a deliberate fusion of state capacity and grassroots participation, weaving administrative efficiency together with community ownership to ensure that benefits reach the last citizen.
Synonyms
Antonyms
Word Family
fuse (v/n), fused (adj), fusible (adj), infuse (v), diffuse (v/adj), transfusion (n)
Root
Latin fūsiō = a melting/pouring; fundere = to pour, melt + -ion = process/result
Etymology
From Latin fūsiō ("a melting, pouring"), from fundere ("to pour, melt").
Memory Hook
Think 'fuse' — when you fuse two wires, they pour together into one; from Latin fundere, 'to pour/melt', the same root as 'foundry' where metals are melted and merged.
How This Word Works in UPSC Writing
The combining of light nuclei into a heavier one with release of energy. The comparison with fission is the examinable content and runs along four axes: fusion releases more energy per unit mass, its fuel is effectively unlimited since deuterium can be obtained from seawater, it produces no long-lived high-level radioactive waste, and it cannot run away, because the reaction requires conditions so extreme that any disturbance extinguishes it rather than accelerating it. The difficulty is precisely that last property, since sustaining temperatures of the order of a hundred million degrees while confining a plasma that can touch no material wall is what magnetic confinement in a tokamak attempts, and the condition for net energy gain is expressed by the Lawson criterion combining density, temperature and confinement time. The Sun performs the same reaction using gravitational confinement, which no terrestrial device can reproduce, which is why the engineering problem is not simply one of scale.
Don’t Confuse It With
Fusion joins light nuclei and fission splits heavy ones, and both release energy because the products are more tightly bound, which the binding energy per nucleon curve peaking near iron explains at a single stroke. Magnetic confinement holds a plasma in a field, as in a tokamak, whereas inertial confinement compresses a fuel pellet with lasers. Plasma is the ionised state matter assumes at fusion temperatures. The Lawson criterion states the combination of density, temperature and confinement time required for net energy gain.
Hindi Meaning
संलयन (sanlayan); प्लाज़्मा (plasma) retained as it stands.
Common Questions
- Why is fusion harder to achieve than fission?
- Fission proceeds at ordinary temperatures once neutrons are available, whereas fusion requires temperatures of order a hundred million degrees and confinement of a plasma that cannot touch any material wall.
- Why do both fusion and fission release energy?
- Because the binding energy per nucleon peaks near iron, so joining nuclei lighter than iron and splitting nuclei heavier than iron both move matter towards more tightly bound configurations.
Seen in UPSC Question Papers
- Prelims 2016 — Nuclear Technology
- Prelims 2015 — Physics
Real UPSC previous-year questions whose text uses “Fusion” — proof this word earns its place on your list.
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