Irodov – Problems in General Physics

2.40. The work in the adiabatic process is n = (iv -
-1)/(y — 1) In n = 1.4 times greater.
2.41. T = To [(71 + 1) 2 /401-1)/ 2.
2.42. v = 112yRT1(y — 1) M = 3.3 km/s.
2.43. Q = RAT (2 — y)/(y — 1).
2.45. Cr, = R (n — 7)/(n — — 1); Cn < 0 for 1 < n < T.
2.46. C = R (n y)1 (n — 1) (y — 1) = —4.2 J/(K•mol), where
n= In 13/In a.
2.47. (a) Q = R (n — y) AT 1(n — 1) (y — 1) = 0.11 kJ; (b)
A = —RAT1(n — 1) = 0.43 kJ.

(a)

(6) I

Fig. 13.

2.48. (a) AU = aV,;(11 2 — 1)/(y — 1); (b) A = 112 aq (11 (^2) — 1);
(c) C = 1 / 2 R (y + 1)/(y — 1).
2.49. (a) C = —R/(y — 1); (b) TV(Y-1-)/ = const; (c) 2 A =
= 2RT 0 (1 — -Y)12)/(7 - 1 ).
2.50. (a) A = (1 — a) RAT; (b) C = R/(y — 1) + R (1 — a);
C < 0 for a > y/(y — 1).
2.51. (a) A = AU (y — 1)/a; Q = AU El (y — 1)/al; (b) C
= R1(y — 1) + R/a.
2.52. (a) C = Cv + R/aV; (b) C = Cv + R/(1 + aV).
2.53. (a) C = TR/(y — 1) + aR/P 017 ; (^) (b) AU = Po (V2 -

- Vi)/(y — 1); A = Po (V2 — V1) - 1 - a In (v 21v1); Q = w (V2

— 1) + a In (V^2 /V^1 ).
2.54. (a) C = Cp + RTolaV; (b) Q = aEp (V 2 — V 1 ) +
RT 0 In (V 2 /V 1 ).
2.55. (a) Ve - 21 7R = const; (b) TeR/fw = const; (c) V — aT
= const.
2.56. (a) A = a In II —RT 0 (— 1)/(y —1); (b) p 1 - VY ea (v-i)/pv,.
= const.
V2
—b

2.57. A=RT —b^1

In —+ a Fi

(

V2 VI

-----) where a and b are Van

der Waals constants.

2.58. (a) AU= alV alV 2 = 0.11 kJ; (b) Q=RT in V2 - b =

=3.8 kJ.