There is no energy or mass transfer across the boundary

There is no mass transfer, but energy transfer exists

There is no energy transfer, but mass transfer exists

Both energy and mass transfer take place across the boundary, but mass transfer is controlled by valves

at a temperature of -273 K

under vacuum condition

at the earth's centre

when molecular momentum of system becomes zero

Two thermodynamics systems are always in thermal equilibrium with each other

If two systems are in thermal equilibrium, then the third system will also be in thermal equilibrium

Two systems not in thermal equilibrium with a third system will also not be in thermal equilibrium with each other

When two systems are in thermal equilibrium with a third system they are in thermal equilibrium with each other

Insulated pipes carrying hot water

Refrigerator freezer coil

Boiler furnaces

Condensation of steam in a condenser

Idling

Cruising

Braking

Decelerating