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A symmetric double convex lens is cut in two equal parts by a plane perpendicular to the principal axis. If the power of the original lens was 4 D, the power of a divided lens will be
Leaving ahead all mathematical formulations, we can answer this by simple intuition. Even after cutting the lens, if we place them together and provide rays of light, commonly we know, it will generate the same image point. So, still, the combined power is 4D. But, after cutting the they became regular and exactly equal halves. And also Power is a scalar property, hence power of each lens, must be 2D.
Figure (18-Q3) shows three transparent media of refractive indices μ1, μ2 and μ3. A point object O is placed in the medium μ2. If the entire medium on the right of the spherical surface has refractive index μ1, the image forms at O’. If this entire medium has refractive index μ3, the image forms at O’’. In the situation shown,
A point object O is placed on the principal axis of a convex lens of focal length f= 20 cm at a distance of 40 cm to the left of it. The diameter of the lens is 10 cm. An eye is placed 60 cm to right of the lens and a distance h below the principal axis. The maximum value of h to see the image is