Ductility of a material is defined as as the amount of plastic deformation of a material. It has nothing to do with elastic deformation within elastic limit.

If Plastic deformation is more than 5% then that material is considered as ductile material or else brittle material.

So rubber has plastic deformation less than 5% so it is Brittle material.

In this quiz poll people who will approach with graph will mark Isobaric, but in the question it says for a given heat amount.
Hence by using 1st law Isothermal will be the answer.

Yes, H =U + PV
Since in Thermodynamics U and PV terms were coming very frequently so people decided to frame this a new term known as Enthalpy.
Hence no such assumptions required to apply this equation.

Shear Stress only distorts the body there is no change in volume.
In the stress strain graph of Mild Steel after lower yield point there is a plane region where volume can be assumed to be constant due to shear deformatiin of planes.

The flat part shows there is shear deformation of planes.
That is why in many production problem we equate initial and final volume.

The lesser the moisture content the more ability of air to gain moisture increases.
As air particles loses heat inturn to absorb more moisture the lesser will be the wet bulb temperature. So more will be the Wet Bulb Depression.

Consider thin pressure vessel 👆