Consider the following information regarding the purchase of pens and penciles by the three students Ravi, Twinkle and Lal from a shop.
Represent the above data in the form of a `3xx2` matrix. What does the entry in the `2^nd` row and in the first column represent?

For an ideal gas, an illustration of three different paths A, (B +C) and (D+E) from an initial state P _(1) , V _(1), T _(1) to a final state P _(2), V _(2), T _(1) is shown in the given Path A represents a reversible isothermal expansion from P _(1), V _(1), to P _(2), V _(2) Path (B +C) represents a reversible adiabatic expansion (B) from P _(1), V _(1), T _(1) to P _(3), V _(2) , T _(2) followed by reversible heating the gas at constant volume (C) from P _(3), V _(2), T _(2) to P _(2), V _(2), T _(1). Path (D+E) represents a reversible expansion at constant pressure P _(1) from P _(1) , V _(1), T _(1) to P _(1), V _(2), T _(3) followed by a reversible cooling at constant volume V _(2) (E) frm V _(1) , V _(2) T _(3) to P _(2) , V _(2), T _(1). What is Delta S for path A ?

For an ideal gas, an illustration of three different paths A, (B +C) and (D+E) from an initial state P _(1) , V _(1), T _(1) to a final state P _(2), V _(2), T _(1) is shown in the given Path A represents a reversible isothermal expansion from P _(1), V _(1), to P _(2), V _(2) Path (B +C) represents a reversible adiabatic expansion (B) from P _(1), V _(1), T _(1) to P _(3), V _(2) , T _(2) followed by reversible heating the gas at constant volume (C) from P _(3), V _(2), T _(2) to P _(2), V _(2), T _(1). Path (D+E) represents a reversible expansion at constant pressure P _(1) from P _(1) , V _(1), T _(1) to P _(1), V _(2), T _(3) followed by a reversible cooling at constant volume V _(2) (E) frm V _(1) , V _(2) T _(3) to P _(2) , V _(2), T _(1). What is q _(rav), for path (A) ?

For an ideal gas, an illustration of three different paths A, (B +C) and (D+E) from an initial state P _(1) , V _(1), T _(1) to a final state P _(2), V _(2), T _(1) is shown in the given Path A represents a reversible isothermal expansion from P _(1), V _(1), to P _(2), V _(2) Path (B +C) represents a reversible adiabatic expansion (B) from P _(1), V _(1), T _(1) to P _(3), V _(2) , T _(2) followed by reversible heating the gas at constant volume (C) from P _(3), V _(2), T _(2) to P _(2), V _(2), T _(1). Path (D+E) represents a reversible expansion at constant pressure P _(1) from P _(1) , V _(1), T _(1) to P _(1), V _(2), T _(3) followed by a reversible cooling at constant volume V _(2) (E) frm V _(1) , V _(2) T _(3) to P _(2) , V _(2), T _(1). What is Delta S for path A ?