Spherical Surface and Lenses, Lens Formula, Magnification, Combination of Lens.
Ray Optics

282508 An achromatic convergent system of focal length \(+20 \mathrm{~cm}\) is made of two lenses (in contact) of materials having dispersive powers in the ratio \(1: 2\). Their focal lengths must be respectively

1 \(10 \mathrm{~cm},-20 \mathrm{~cm}\)
2 \(20 \mathrm{~cm}, 10 \mathrm{~cm}\)
3 \(-10 \mathrm{~cm},-20 \mathrm{~cm}\)
4 \(20 \mathrm{~cm},-10 \mathrm{~cm}\)
Ray Optics

282509 Figure shows two convex lenses \(P\) and \(Q\), each made up of three different transparent materials. The number of images formed of an object kept on the principal axis of lenses \(P\) and \(Q\) respectively

1 3 and 1
2 3 and 3
3 3 and 2
4 1 and 3
Ray Optics

282510 A plano-convex glass lens \(\left(\mu_{\mathrm{g}}=3 / 2\right)\) of radius of curvature \(R=20 \mathrm{~cm}\) is placed at a distance ' \(a\) ' from a concave lens of focal length \(40 \mathrm{~cm}\). What should be the distance ' \(b\) ' of a point object \(O\) from plano-convex lens so that the position of final image a independent of a?

1 \(20 \mathrm{~cm}\)
2 \(60 \mathrm{~cm}\)
3 \(40 \mathrm{~cm}\)
4 \(30 \mathrm{~cm}\)
Ray Optics

282511 A luminous object is placed at a distance of 30 cm from the convex lens of focal length \(20 \mathrm{~cm}\). On the other side of the lens, at what distance from the lens a convex mirror of radius of curvature \(10 \mathrm{~cm}\) be placed in order to have an upright image of the object coincident with it?

1 \(60 \mathrm{~cm}\)
2 \(50 \mathrm{~cm}\)
3 \(30 \mathrm{~cm}\)
4 \(20 \mathrm{~cm}\)
Ray Optics

282508 An achromatic convergent system of focal length \(+20 \mathrm{~cm}\) is made of two lenses (in contact) of materials having dispersive powers in the ratio \(1: 2\). Their focal lengths must be respectively

1 \(10 \mathrm{~cm},-20 \mathrm{~cm}\)
2 \(20 \mathrm{~cm}, 10 \mathrm{~cm}\)
3 \(-10 \mathrm{~cm},-20 \mathrm{~cm}\)
4 \(20 \mathrm{~cm},-10 \mathrm{~cm}\)
Ray Optics

282509 Figure shows two convex lenses \(P\) and \(Q\), each made up of three different transparent materials. The number of images formed of an object kept on the principal axis of lenses \(P\) and \(Q\) respectively

1 3 and 1
2 3 and 3
3 3 and 2
4 1 and 3
Ray Optics

282510 A plano-convex glass lens \(\left(\mu_{\mathrm{g}}=3 / 2\right)\) of radius of curvature \(R=20 \mathrm{~cm}\) is placed at a distance ' \(a\) ' from a concave lens of focal length \(40 \mathrm{~cm}\). What should be the distance ' \(b\) ' of a point object \(O\) from plano-convex lens so that the position of final image a independent of a?

1 \(20 \mathrm{~cm}\)
2 \(60 \mathrm{~cm}\)
3 \(40 \mathrm{~cm}\)
4 \(30 \mathrm{~cm}\)
Ray Optics

282511 A luminous object is placed at a distance of 30 cm from the convex lens of focal length \(20 \mathrm{~cm}\). On the other side of the lens, at what distance from the lens a convex mirror of radius of curvature \(10 \mathrm{~cm}\) be placed in order to have an upright image of the object coincident with it?

1 \(60 \mathrm{~cm}\)
2 \(50 \mathrm{~cm}\)
3 \(30 \mathrm{~cm}\)
4 \(20 \mathrm{~cm}\)
Ray Optics

282508 An achromatic convergent system of focal length \(+20 \mathrm{~cm}\) is made of two lenses (in contact) of materials having dispersive powers in the ratio \(1: 2\). Their focal lengths must be respectively

1 \(10 \mathrm{~cm},-20 \mathrm{~cm}\)
2 \(20 \mathrm{~cm}, 10 \mathrm{~cm}\)
3 \(-10 \mathrm{~cm},-20 \mathrm{~cm}\)
4 \(20 \mathrm{~cm},-10 \mathrm{~cm}\)
Ray Optics

282509 Figure shows two convex lenses \(P\) and \(Q\), each made up of three different transparent materials. The number of images formed of an object kept on the principal axis of lenses \(P\) and \(Q\) respectively

1 3 and 1
2 3 and 3
3 3 and 2
4 1 and 3
Ray Optics

282510 A plano-convex glass lens \(\left(\mu_{\mathrm{g}}=3 / 2\right)\) of radius of curvature \(R=20 \mathrm{~cm}\) is placed at a distance ' \(a\) ' from a concave lens of focal length \(40 \mathrm{~cm}\). What should be the distance ' \(b\) ' of a point object \(O\) from plano-convex lens so that the position of final image a independent of a?

1 \(20 \mathrm{~cm}\)
2 \(60 \mathrm{~cm}\)
3 \(40 \mathrm{~cm}\)
4 \(30 \mathrm{~cm}\)
Ray Optics

282511 A luminous object is placed at a distance of 30 cm from the convex lens of focal length \(20 \mathrm{~cm}\). On the other side of the lens, at what distance from the lens a convex mirror of radius of curvature \(10 \mathrm{~cm}\) be placed in order to have an upright image of the object coincident with it?

1 \(60 \mathrm{~cm}\)
2 \(50 \mathrm{~cm}\)
3 \(30 \mathrm{~cm}\)
4 \(20 \mathrm{~cm}\)
Ray Optics

282508 An achromatic convergent system of focal length \(+20 \mathrm{~cm}\) is made of two lenses (in contact) of materials having dispersive powers in the ratio \(1: 2\). Their focal lengths must be respectively

1 \(10 \mathrm{~cm},-20 \mathrm{~cm}\)
2 \(20 \mathrm{~cm}, 10 \mathrm{~cm}\)
3 \(-10 \mathrm{~cm},-20 \mathrm{~cm}\)
4 \(20 \mathrm{~cm},-10 \mathrm{~cm}\)
Ray Optics

282509 Figure shows two convex lenses \(P\) and \(Q\), each made up of three different transparent materials. The number of images formed of an object kept on the principal axis of lenses \(P\) and \(Q\) respectively

1 3 and 1
2 3 and 3
3 3 and 2
4 1 and 3
Ray Optics

282510 A plano-convex glass lens \(\left(\mu_{\mathrm{g}}=3 / 2\right)\) of radius of curvature \(R=20 \mathrm{~cm}\) is placed at a distance ' \(a\) ' from a concave lens of focal length \(40 \mathrm{~cm}\). What should be the distance ' \(b\) ' of a point object \(O\) from plano-convex lens so that the position of final image a independent of a?

1 \(20 \mathrm{~cm}\)
2 \(60 \mathrm{~cm}\)
3 \(40 \mathrm{~cm}\)
4 \(30 \mathrm{~cm}\)
Ray Optics

282511 A luminous object is placed at a distance of 30 cm from the convex lens of focal length \(20 \mathrm{~cm}\). On the other side of the lens, at what distance from the lens a convex mirror of radius of curvature \(10 \mathrm{~cm}\) be placed in order to have an upright image of the object coincident with it?

1 \(60 \mathrm{~cm}\)
2 \(50 \mathrm{~cm}\)
3 \(30 \mathrm{~cm}\)
4 \(20 \mathrm{~cm}\)