The critical nucleus size (in mm) when copper melt is under-cooled by 100K is
Given data:
Melting point: 1356 K
Density: 8900 kg.m^-3
Solid-liquid interfacial energy: 0.5 Jm^-2
Latent heat of freezing: 13000 J. mol^-1
Molar volume: 7 × 10^-6 m³ mol^-1

A. Dislocation pile-up B. Large number of slip systems C. Low stacking faultenergy D. Dislocation climb

A. Lamellar B. Widmanstatten C. Acicular D. Nodular

A. decreases because the oxygen ions supplied by the sodium oxide break the chain structure of the silicate slag B. increases because the oxygen ion supplied by the sodium oxide further add to the oxygen network in the slag C. remains unaffected because fundamentally one can not distinguish between the oxygen ions supplied by the sodium oxide and those already present in the slag D. remains unaffected because the oxygen ions fill up the holes and vacancies present in the liquid slag

A. P-4, Q-3, R-2, S-1 B. P-1, Q-2, R-3, S-4 C. P-2, Q-4, R-1, S-3 D. P-2, Q-4, R-3, S-1