A concave lens of glass of refractive index 1.5, has both surfaces of same radius of curvature R. On immersion in a medium of refractive index 1.75, the lens will behave as a
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convergent lens of focal length 3.5 R
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convergent lens of focal length 3.0 R
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divergent lens of focal length 3.5 R
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divergent lense of focal length 3.0 R