The circular weft knitting machine that rotates in clockwise direction demands 'z' twist yarn that 's' twist yarn because 'z' twist yarn

The Pressley index is the ratio between

The woven fabric air permeability is expressed in

The breaking load of a 200 denier multifilament yarn containing 130 filaments found to be 800 gram force. Its tensile strength in gram force/denier is

When the electrical field parallel to the fibre axis, the refractive index will be

Which one of the following equation is used to calculate the work factor ?