17) The use of archemedian spiral curve is made in........
a) Teeth profiles of helical gears
b) Profiles of cams
c) Both a & b
d) None of these
18) The cams are widely used in........
a) Automates
b) Printing machines
c) C engines
d) All of these
19) Spring index =
a) Diameter of coil / diameter of a wire
b) Diameter of wire /diameter of coil
c) Mean diameter of wire / diameter of coil
d) Mean diameter of a coil / diameter of wire
20) Eccentricity =
a) Distance of a point from the focus / distance of the point from directrix
b) Distance of focus from point / distance of point from
c) Distance of point from focus / distance of directrix of point
d) Distance of point from directrix / distance of point from focus