Engineering Thermodynamics The value of n = 1 in the polytropic process indicates it to be

Isothermal process
Reversible process
Irreversible process

Engineering Thermodynamics The general gas energy equation is (where Q1 - 2 = Heat supplied, dU = Change in internal energy, and W1 - 2 = Work done in heat units)

Q1 - 2 = dU × W1 - 2
Q1 - 2 = dU + W1 - 2
Q1 - 2 = dU - W1 - 2
Q1 - 2 = dU/W1 - 2

Engineering Thermodynamics Otto cycle consists of following four processes

Two isentropic, one constant volume and one constant pressure
Two isentropic and two constant pressures
Two isothermal and two isentropic
Two isentropic and two constant volumes

Engineering Thermodynamics Diesel cycle consists of following four processes

Two isothermal and two isentropic
Two isentropic, one constant volume and one constant pressure
Two isentropic and two constant pressures
Two isentropic and two constant volumes

Engineering Thermodynamics Brayton cycle consists' of following four processes

Two isentropic, one constant volume and one constant pressure
Two isothermal and two isentropic
Two isentropic and two constant pressures
Two isentropic and two constant volumes