Thermodynamics

11: The thermal efficiency of an ideal gas turbine plant is given by (where r = Pressure ratio)

A. `r^(Y - 1)`

B. `1 -r^(Y - 1)`

C. `1 - (1/r)^(Y//Y - 1)`

D. `1 - (1/r)^(Y - 1//Y)`

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12: Workdone during adiabatic expansion is given by (where p₁ v₁, T₁ = Pressure, volume and temperature for the initial condition of gas, p₂, v₂, T₂ = Corresponding values for the final condition of gas, R = Gas constant, and Î³ = Ratio of specific heats)

A. `(P_1V_1 - P_2 V_2)/(Y - 1)`

B. `(mR(T_1 - T_2))/(Y - 1)`

C. `(mRT_1)/(Y - 1) (1 - (P_2V_2)/(P_1V_1))`

D. all of these

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13: The heat absorbed or rejected by the working substance is given by (where ds = Increase or decrease of entropy, T = Absolute temperature, and dQ = Heat absorbed or rejected)

A. `delta`Q = T.ds

B. `delta`Q = T/ds

C. dQ = ds/

D. none of these

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14: The root mean square velocity of the gas molecules is given by (where k = Boltzmann's constant, T = Absolute temperature, and m = Mass of one molecule of a gas)

A. `sqrt((kT)/(m))`

B. `sqrt((2kT)/(m))`

C. `sqrt((3kT)/(m))`

D. `sqrt((5kT)/(m))`

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15: The expansion ratio (r) is the ratio of (where v₁ = Volume at the beginning of expansion, and v₂ = Volume at the end of expansion)

A. `V_1/V_2`

B. `V_2/V_1`

C. `(V_1 + V_2)/(V_1)`

D. `(V_1 + V_2)/(V_2)`

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