Consider the process on a system shown in figure. During the process, the work done by the system आकृति में दिखाए गए सिस्टम की प्रक्रिया पर विचार करें। प्रक्रिया के दौरान, सिस्टम द्वारा किया गया कार्य A. Continuously increases B. Continuously decreases C. First increases then decreases D. First decrease then increases

A point source of light S is placed on the axis of a lens of focal length 20cm at a distance 25cm from lense. A screen is placed normal to the axis of lens at a distance x from it (treat all rays as paraxial). Identify the true or false statements. a. As x is increased from zero , intensity continuously decreases. b. As x is increased from zero, intensity first increases then decreases. c. Intensity at center of screen for x =90 cm and x=110 cm is same.

A point source of light S is placed on the axis of a lens of focal length 20cm at a distance 25cm from lense. A screen is placed normal to the axis of lens at a distance x from it (treat all rays as paraxial). Identify the true or false statements. a. As x is increased from zero , intensity continuously decreases. b. As x is increased from zero, intensity first increases then decreases. c. Intensity at center of screen for x =90 cm and x=110 cm is same.

PQ is a smooth inclined plane whose angle theta can be varied in such a way that point Q remains fixed and P can move on a vertical line PR . A particle slides from rest from point P at different value of theta time for descent from P and Q is noted. The following statement (s) is // are correct about the time of descent : A. the minimum time of descent is 2sqrt(l//g) B. the time descent is minimum continuously as theta is increased C. the time of descent decreases continuously as theta is increased D. the time of descent first decreases then increases.

An ideal gas is taken from the state. A (pressure p, volume V) to the state B (pressure p/2, volume 2V) along a straight line path in the p-V diagram. (T - True & F - False) S_1 : The work done by the gas in the gas in process A to B exceeds the work that would be done by it if the system were taken from A to B along the isotherm. S_2 : In going from A to B, the temperature T of the gas first increases to a maximum value and then decreases. S_3 : Work done by the gas is negative as pressure is decreasing.

Work done by the system in isothermal reversible process is w_(rev.)= -2.303 nRT "log"(V_(2))/(V_(1)) . Also in case of adiabatic reversible process work done by the system is given by: w_(rev.) = (nR)/(gamma -1) [T_2 - T_1] . During expansion disorder increases and the increase in disorder is expressed in terms of change in entropy DeltaS = q_(rev.)/T . The entropy changes also occurs during transformation of one state to other end expressed as DeltaS = DeltaH/T . Both entropy and enthalpy changes obtained for a process were taken as a measure of spontaniety of process but finally it was recommended that decrease in free energy is responsible for spontaniety and DeltaG=DeltaH - T DeltaS . A chemical change will definitely be spontaneous if:

Work done by the system in isothermal reversible process is w_(rev.)= -2.303 nRT "log"(V_(2))/(V_(1)) . Also in case of adiabatic reversible process work done by the system is given by: w_(rev.) = (nR)/(gamma -1) [T_2 - T_1] . During expansion disorder increases and the increase in disorder is expressed in terms of change in entropy DeltaS = q_(rev.)/T . The entropy changes also occurs during transformation of one state to other end expressed as DeltaS = DeltaH/T . Both entropy and enthalpy changes obtained for a process were taken as a measure of spontaniety of process but finally it was recommended that decrease in free energy is responsible for spontaniety and DeltaG=DeltaH - T DeltaS . The heat of vaporisation and heat of fusion of H_2O are 540 cal//g and 80 cal//g . This ratio of (DeltaS_(vap.))/(DeltaS_("fusion")) for water is:

Work done by the system in isothermal reversible process is w_(rev.)= -2.303 nRT "log"(V_(2))/(V_(1)) . Also in case of adiabatic reversible process work done by the system is given by: w_(rev.) = (nR)/(gamma -1) [T_2 - T_1] . During expansion disorder increases and the increase in disorder is expressed in terms of change in entropy DeltaS = q_(rev.)/T . The entropy changes also occurs during transformation of one state to other end expressed as DeltaS = DeltaH/T . Both entropy and enthalpy changes obtained for a process were taken as a measure of spontaniety of process but finally it was recommended that decrease in free energy is responsible for spontaniety and DeltaG=DeltaH - T DeltaS . Which statements are correct? (1) The expansion work for a gas into a vacuum is equal to zero. (2) 1 mole of a gas occupying 3 litre volume on expanding to 15 litre at constant pressure of 1atm does expansion work 1.215 kJ . (3) The maximum work done during expansion of 16gO_2 at 300K from 5dm^3 to 25 dm^3 is 2.01 kJ . (4) The DeltaS for S to L is almost negligible in comparision to DeltaS for L to G . (5) DeltaS = 2.303 nR "log"(V_(2))/(V_(1)). (at constant T )

Work done by the system in isothermal reversible process is w_(rev.)= -2.303 nRT "log"(V_(2))/(V_(1)) . Also in case of adiabatic reversible process work done by the system is given by: w_(rev.) = (nR)/(gamma -1) [T_2 - T_1] . During expansion disorder increases and the increase in disorder is expressed in terms of change in entropy DeltaS = q_(rev.)/T . The entropy changes also occurs during transformation of one state to other end expressed as DeltaS = DeltaH/T . Both entropy and enthalpy changes obtained for a process were taken as a measure of spontaniety of process but finally it was recommended that decrease in free energy is responsible for spontaniety and DeltaG=DeltaH - T DeltaS . Ag_2O_((s)) to 2Ag_((s)) + 1/2 O_(2(g)) attains equilibrium at temperature… K is : (The DeltaH and DeltaS for the reaction are 30.5kJ mol^(-1) and 66J mol^(-1) K^(-1) )