Engineering Thermodynamics
In order that a cycle be reversible, following must be satisfied

When beat is being rejected, temperature of cold source and working substance should be same
When heat is being absorbed, temperature of hot source and working substance should be same
All of these
Free expansion or friction resisted expansion/compression process should not be encountered

ANSWER DOWNLOAD EXAMIANS APP

Engineering Thermodynamics
Carbonization of coal consists of

Drying and crushing the coal to a fine powder
None of these
Heating the wood with a limited supply of air to temperature not less than 280°C
Moulding the finely ground coal under pressure with or without a binding material

ANSWER DOWNLOAD EXAMIANS APP