Work done on (or) by a thermodynamic system is zero in which of the following processes?

If $R$ be the universal gas constant then, the amount of heat required to raise the temperature of $2$ moles of monoatomic gas under isobaric condition from $0°\mathrm{C}$ to $100°\mathrm{C}$ will be:

Figure below shows a cyclic process $abcda.$. If $\Delta Q$ be the heat supplied to the system. $\mathrm{\Delta }U$ be the change in internal energy and $\Delta W$ be the work done by the system, then which of the following relation is correct ?

What amount of heat is to be supplied to $4\times {10}^{-2} \mathrm{kg}$ of Nitrogen at room temperature, to rise its temperature by $50°\mathrm{C},$ at a constant pressure? $\left(R=8.3 \mathrm{J}.{\mathrm{mol}}^{-1}·{\mathrm{K}}^{-1}\right.$and molecular weight of nitrogen is $28 )$

Two moles of helium gas are taken along the path $ABCD$ (as shown). The work done by the gas is _______