282346 A convergent lens is placed \(40 \mathrm{~cm}\) to the right of a diverging lens of focal length \(15 \mathrm{~cm}\). A parallel beam of light enters the divergent lens from the left. And the beam is again parallel when it emerges from the convergent lens. The focal length of the convergent lens is-

282347 Two lenses of powers \(-1.75 \mathrm{D}\) and \(+2.25 \mathrm{D}\) are placed in contact. The focal length of the combination is-

282348 The radii of curvature of a double convex lens are \(4 \mathrm{~cm}\) and \(8 \mathrm{~cm}\). If the refractive index of the material of the lens is 1.5 , the focal length of the lens is nearly

282349 Two thin lenses of powers \(+12 D\) and \(-2 D\) respectively are kept side by side. The focal length of the combination is

282350 A concave lens of focal length \(f\) produces an image \(\frac{1}{n}\) times that of the size of the object. The distance of the object from the lens is:

282346 A convergent lens is placed \(40 \mathrm{~cm}\) to the right of a diverging lens of focal length \(15 \mathrm{~cm}\). A parallel beam of light enters the divergent lens from the left. And the beam is again parallel when it emerges from the convergent lens. The focal length of the convergent lens is-

282347 Two lenses of powers \(-1.75 \mathrm{D}\) and \(+2.25 \mathrm{D}\) are placed in contact. The focal length of the combination is-

282348 The radii of curvature of a double convex lens are \(4 \mathrm{~cm}\) and \(8 \mathrm{~cm}\). If the refractive index of the material of the lens is 1.5 , the focal length of the lens is nearly

282349 Two thin lenses of powers \(+12 D\) and \(-2 D\) respectively are kept side by side. The focal length of the combination is

282350 A concave lens of focal length \(f\) produces an image \(\frac{1}{n}\) times that of the size of the object. The distance of the object from the lens is:

282346 A convergent lens is placed \(40 \mathrm{~cm}\) to the right of a diverging lens of focal length \(15 \mathrm{~cm}\). A parallel beam of light enters the divergent lens from the left. And the beam is again parallel when it emerges from the convergent lens. The focal length of the convergent lens is-

282347 Two lenses of powers \(-1.75 \mathrm{D}\) and \(+2.25 \mathrm{D}\) are placed in contact. The focal length of the combination is-

282348 The radii of curvature of a double convex lens are \(4 \mathrm{~cm}\) and \(8 \mathrm{~cm}\). If the refractive index of the material of the lens is 1.5 , the focal length of the lens is nearly

282349 Two thin lenses of powers \(+12 D\) and \(-2 D\) respectively are kept side by side. The focal length of the combination is

282350 A concave lens of focal length \(f\) produces an image \(\frac{1}{n}\) times that of the size of the object. The distance of the object from the lens is:

282346 A convergent lens is placed \(40 \mathrm{~cm}\) to the right of a diverging lens of focal length \(15 \mathrm{~cm}\). A parallel beam of light enters the divergent lens from the left. And the beam is again parallel when it emerges from the convergent lens. The focal length of the convergent lens is-

282347 Two lenses of powers \(-1.75 \mathrm{D}\) and \(+2.25 \mathrm{D}\) are placed in contact. The focal length of the combination is-

282348 The radii of curvature of a double convex lens are \(4 \mathrm{~cm}\) and \(8 \mathrm{~cm}\). If the refractive index of the material of the lens is 1.5 , the focal length of the lens is nearly

282349 Two thin lenses of powers \(+12 D\) and \(-2 D\) respectively are kept side by side. The focal length of the combination is

282350 A concave lens of focal length \(f\) produces an image \(\frac{1}{n}\) times that of the size of the object. The distance of the object from the lens is:

282346 A convergent lens is placed \(40 \mathrm{~cm}\) to the right of a diverging lens of focal length \(15 \mathrm{~cm}\). A parallel beam of light enters the divergent lens from the left. And the beam is again parallel when it emerges from the convergent lens. The focal length of the convergent lens is-

282347 Two lenses of powers \(-1.75 \mathrm{D}\) and \(+2.25 \mathrm{D}\) are placed in contact. The focal length of the combination is-

282348 The radii of curvature of a double convex lens are \(4 \mathrm{~cm}\) and \(8 \mathrm{~cm}\). If the refractive index of the material of the lens is 1.5 , the focal length of the lens is nearly

282349 Two thin lenses of powers \(+12 D\) and \(-2 D\) respectively are kept side by side. The focal length of the combination is

282350 A concave lens of focal length \(f\) produces an image \(\frac{1}{n}\) times that of the size of the object. The distance of the object from the lens is: