A biconvex lens \((\mu=1.5)\)  has a radius of curvature of magnitude \(20~\text{cm}\). Which one of the following options, best describes, the image formed by an object of height \(2\) cm placed \(30~\text{cm}\) from the lens?
1. virtual, upright, height \(=0.5\) cm
2. real, inverted, height \(=4\) cm
3. real, inverted, height \(=1\) cm
4. virtual, upright, height \(=1\) cm
Subtopic:  Lenses | Lens Makers' Formula | Refraction at Curved Surface |
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AIPMT - 2011
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A point object \((A)\) is placed on the principal axis of a convex lens (focal length = \(30\) cm) at a distance of \(45\) cm from it. The image is formed at position \(B.\) If the object \(A\) is moved up by \(1\) cm then the image moves:
         
1. down by \(1\) cm
2. down by \(2\) cm
3. up by \(1\) cm
4. up by \(2\) cm
Subtopic:  Lenses |
 59%
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A parallel beam of width \(20\) mm is incident onto a lens and the width of the emerging beam decreases at a rate of \(1\) mm as it travels every \(3\) cm. The lens has a focal length of:
1.  \(30\) cm
2.  \(60\) cm
3.  \(\frac{20}3\) cm
4.  \(\frac{40}{3}\) cm
Subtopic:  Lenses |
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A biconvex lens has radii of curvature, \(20\) cm each. If the refractive index of the material of the lens is \(1.5,\) the power of the lens is:
1. infinity
2. \(+2\) D
3. \(+20\) D
4. \(+5\) D
Subtopic:  Lenses |
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NEET - 2022
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A concave lens of focal length \(-25\) cm is sandwiched between two convex lenses, each of focal length, \(40\) cm. The power in dioptre of the combined lens would be:
                  

1. \(55\) 2. \(9\)
3. \(1\) 4. \(0.01\)
Subtopic:  Lenses |
 63%
From NCERT
NEET - 2022
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