At what cold-reservoir temperature (in ∘c) would a carnot engine with a hot-reservoir temperature of 420 ∘c have an efficiency of 60 % ?

Tc = 168°C

Explanation:

Carnot engine:

ε = 1 - Tc/Th

∴ ε: efficiency = 60% = 0.60

∴ Th: hot-reservoir temperature = 420°C

∴ Tc: cold-reservoir temperature = ?

⇒ Tc = (1 - ε)×Th

⇒ Tc = ( 1 - 0.60 )×( 420 °C )

⇒ Tc = 168°C

There is one s orbital, and there are three p orbitals, five d orbitals, and seven f orbitals. thus, the answer is b. do not confuse the number of orbitals in a subshell with the number of electrons the subshell can hold. each orbital can hold two electrons, so the capacity of an nf subshell is 14 electrons.

Aphysical change is one that you can put in and remove like a ham sandwich. the stuff you put in there can be changem its not permanet. a chemical change is on that can't be change thats permanet. like when you make a cake and bake it. you can't get those ingredients back.