`1` If r and R be the radii of inner and outer circles respectively, then area of ring is

{:(,"Column A",,"Column B"),(18.,"If r and R be the radii of inner and outer circles, respectively, then area of a ring is _______.",(a),60),(19.,"The total surface area of a cube of edg" sqrt(10) "cm is ______." cm^(2).,(c ),pi (R^^(2)+r^(2))"sq. units"),(21.,"If the radius of the circule is 14 cm, then the area of the sector of angle." 45^(@) "is _______" cm^(2).,(d),pi(R^(2)-r^(2))"sq. units"),(,,(e ),sqrt(20)cm),(,,(f),77 cm^(2)):}

A car is moving on a circular path and takes a turn. If R_(1) and R_(2) be the reactions on the inner and outer wheels, respectively, then

A car is moving on a circular path and takes a turn. If R_(1) and R_(2) be the reactions on the inner and outer wheels, respectively, then

A car is moving on a circular path and takes a turn. If R_(1) and R_(2) be the reactions on the inner and outer wheels, respectively, then

A car is moving on a circular path and takes a turn. If R_(1) and R_(2) be the reactions on the inner and outer wheels, respectively, then

O is the origin & also the centre of two concentric circles having radii of the inner & the outer circle as a & b respectively. A line OPQ is drawn to cut the inner circle in P & the outer circle in Q. PR is drawn parallel to the y -axis & QR is drawn parallel to the x -axis. Prove that the locus of R is an ellipse touching the two circles. If the focii of this ellipse lie on the inner circle, find the ratio of inner: outer radii & find also the eccentricity of the ellipse.

Ois the origin & also the centre of two concentric circles having radii of the inner & the outer circle as a & b respectively. A line OPQ is drawn to cut the inner circle in P & the outer circle in Q. PR is drawn parallel to the y-axis & QR is drawn parallel to the x-axis. Prove that the locus of R is an ellipse touching the two circles. If the focii of this ellipse lie on the inner circle, find the ratio of inner: outer radii & find also the eccentricity of the ellipse.