NEET Test Series from KOTA - 10 Papers In MS WORD
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PHXII09:RAY OPTICS AND OPTICAL INSTRUMENTS
364821
A equi convex lens is of refractive index 1.55 with both faces of same radius of curvature. What is the radius of curvature required if focal length is to be \(20\,cm\)?
364822
The radius of curvature of the curved surface of a plano-convex lens is\(20\;cm\). If the refractive index of the material of the lens is 1.5, it will
1 Act as a concave lens for the objects that lie on its curved side
2 Act as a convex lens for the objects that lie on its curved side
3 Act as a concave lens irrespective of side on which the object lies
4 Act as a convex lens irrespective of the side on which the object lies
Explanation:
Here, \(R = 20\;cm,{\mkern 1mu} \mu = 1.5,\) on substituting the values \(\frac{1}{{{f_1}}} = (\mu - 1)\left( {\frac{1}{\infty } - \frac{1}{{ - R}}} \right)\) \(\frac{1}{{{f_2}}} = (\mu - 1)\left( {\frac{1}{R} - \frac{1}{\infty }} \right)\) For both cases \(f = \frac{R}{{\mu - 1}} = \frac{{20}}{{1.5 - 1}} = 40\,cm\)of converging nature as \(f > 0.\) Therefore, lens act as a convex lens irrespective of the side on which the object lies.
NCERT EXEMPLAR
PHXII09:RAY OPTICS AND OPTICAL INSTRUMENTS
364823
Assertion : When a white light is passed through a lens, violet light is more refracted than red light. Reason : Focal length for red light is greater than violet.
1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.
2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.
3 Assertion is correct but Reason is incorrect.
4 Assertion is incorrect but reason is correct.
Explanation:
When white light passes through a lens, violet (V)light undergoes more refraction than red light (R). This discrepancy occurs because the wavelength of violet light is shorter than that of red light, resulting in the focal length for red light being greater than that for violet light. \(\frac{1}{f} = (\mu - 1)\left( {\frac{1}{{{R_1}}} - \frac{1}{{{R_2}}}} \right)\) \({\mu _R} < {\mu _V}\) So correct option is (1).
PHXII09:RAY OPTICS AND OPTICAL INSTRUMENTS
364824
A convex lens of crown glass \(\left( {n = 1.525} \right)\) will behave as a divergent lens if immersed in
1 In a medium of \(\left( {n = 1.33} \right)\)
2 Water \(\left( {n = 1.33} \right)\)
3 It cannot act as a divergent lens
4 Carbon disulphide \(n = 1.66\)
Explanation:
A lens shows opposite behaviour if \({\mu _{medium}} > {\mu _{lens}}\)
364821
A equi convex lens is of refractive index 1.55 with both faces of same radius of curvature. What is the radius of curvature required if focal length is to be \(20\,cm\)?
364822
The radius of curvature of the curved surface of a plano-convex lens is\(20\;cm\). If the refractive index of the material of the lens is 1.5, it will
1 Act as a concave lens for the objects that lie on its curved side
2 Act as a convex lens for the objects that lie on its curved side
3 Act as a concave lens irrespective of side on which the object lies
4 Act as a convex lens irrespective of the side on which the object lies
Explanation:
Here, \(R = 20\;cm,{\mkern 1mu} \mu = 1.5,\) on substituting the values \(\frac{1}{{{f_1}}} = (\mu - 1)\left( {\frac{1}{\infty } - \frac{1}{{ - R}}} \right)\) \(\frac{1}{{{f_2}}} = (\mu - 1)\left( {\frac{1}{R} - \frac{1}{\infty }} \right)\) For both cases \(f = \frac{R}{{\mu - 1}} = \frac{{20}}{{1.5 - 1}} = 40\,cm\)of converging nature as \(f > 0.\) Therefore, lens act as a convex lens irrespective of the side on which the object lies.
NCERT EXEMPLAR
PHXII09:RAY OPTICS AND OPTICAL INSTRUMENTS
364823
Assertion : When a white light is passed through a lens, violet light is more refracted than red light. Reason : Focal length for red light is greater than violet.
1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.
2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.
3 Assertion is correct but Reason is incorrect.
4 Assertion is incorrect but reason is correct.
Explanation:
When white light passes through a lens, violet (V)light undergoes more refraction than red light (R). This discrepancy occurs because the wavelength of violet light is shorter than that of red light, resulting in the focal length for red light being greater than that for violet light. \(\frac{1}{f} = (\mu - 1)\left( {\frac{1}{{{R_1}}} - \frac{1}{{{R_2}}}} \right)\) \({\mu _R} < {\mu _V}\) So correct option is (1).
PHXII09:RAY OPTICS AND OPTICAL INSTRUMENTS
364824
A convex lens of crown glass \(\left( {n = 1.525} \right)\) will behave as a divergent lens if immersed in
1 In a medium of \(\left( {n = 1.33} \right)\)
2 Water \(\left( {n = 1.33} \right)\)
3 It cannot act as a divergent lens
4 Carbon disulphide \(n = 1.66\)
Explanation:
A lens shows opposite behaviour if \({\mu _{medium}} > {\mu _{lens}}\)
364821
A equi convex lens is of refractive index 1.55 with both faces of same radius of curvature. What is the radius of curvature required if focal length is to be \(20\,cm\)?
364822
The radius of curvature of the curved surface of a plano-convex lens is\(20\;cm\). If the refractive index of the material of the lens is 1.5, it will
1 Act as a concave lens for the objects that lie on its curved side
2 Act as a convex lens for the objects that lie on its curved side
3 Act as a concave lens irrespective of side on which the object lies
4 Act as a convex lens irrespective of the side on which the object lies
Explanation:
Here, \(R = 20\;cm,{\mkern 1mu} \mu = 1.5,\) on substituting the values \(\frac{1}{{{f_1}}} = (\mu - 1)\left( {\frac{1}{\infty } - \frac{1}{{ - R}}} \right)\) \(\frac{1}{{{f_2}}} = (\mu - 1)\left( {\frac{1}{R} - \frac{1}{\infty }} \right)\) For both cases \(f = \frac{R}{{\mu - 1}} = \frac{{20}}{{1.5 - 1}} = 40\,cm\)of converging nature as \(f > 0.\) Therefore, lens act as a convex lens irrespective of the side on which the object lies.
NCERT EXEMPLAR
PHXII09:RAY OPTICS AND OPTICAL INSTRUMENTS
364823
Assertion : When a white light is passed through a lens, violet light is more refracted than red light. Reason : Focal length for red light is greater than violet.
1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.
2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.
3 Assertion is correct but Reason is incorrect.
4 Assertion is incorrect but reason is correct.
Explanation:
When white light passes through a lens, violet (V)light undergoes more refraction than red light (R). This discrepancy occurs because the wavelength of violet light is shorter than that of red light, resulting in the focal length for red light being greater than that for violet light. \(\frac{1}{f} = (\mu - 1)\left( {\frac{1}{{{R_1}}} - \frac{1}{{{R_2}}}} \right)\) \({\mu _R} < {\mu _V}\) So correct option is (1).
PHXII09:RAY OPTICS AND OPTICAL INSTRUMENTS
364824
A convex lens of crown glass \(\left( {n = 1.525} \right)\) will behave as a divergent lens if immersed in
1 In a medium of \(\left( {n = 1.33} \right)\)
2 Water \(\left( {n = 1.33} \right)\)
3 It cannot act as a divergent lens
4 Carbon disulphide \(n = 1.66\)
Explanation:
A lens shows opposite behaviour if \({\mu _{medium}} > {\mu _{lens}}\)
364821
A equi convex lens is of refractive index 1.55 with both faces of same radius of curvature. What is the radius of curvature required if focal length is to be \(20\,cm\)?
364822
The radius of curvature of the curved surface of a plano-convex lens is\(20\;cm\). If the refractive index of the material of the lens is 1.5, it will
1 Act as a concave lens for the objects that lie on its curved side
2 Act as a convex lens for the objects that lie on its curved side
3 Act as a concave lens irrespective of side on which the object lies
4 Act as a convex lens irrespective of the side on which the object lies
Explanation:
Here, \(R = 20\;cm,{\mkern 1mu} \mu = 1.5,\) on substituting the values \(\frac{1}{{{f_1}}} = (\mu - 1)\left( {\frac{1}{\infty } - \frac{1}{{ - R}}} \right)\) \(\frac{1}{{{f_2}}} = (\mu - 1)\left( {\frac{1}{R} - \frac{1}{\infty }} \right)\) For both cases \(f = \frac{R}{{\mu - 1}} = \frac{{20}}{{1.5 - 1}} = 40\,cm\)of converging nature as \(f > 0.\) Therefore, lens act as a convex lens irrespective of the side on which the object lies.
NCERT EXEMPLAR
PHXII09:RAY OPTICS AND OPTICAL INSTRUMENTS
364823
Assertion : When a white light is passed through a lens, violet light is more refracted than red light. Reason : Focal length for red light is greater than violet.
1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.
2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.
3 Assertion is correct but Reason is incorrect.
4 Assertion is incorrect but reason is correct.
Explanation:
When white light passes through a lens, violet (V)light undergoes more refraction than red light (R). This discrepancy occurs because the wavelength of violet light is shorter than that of red light, resulting in the focal length for red light being greater than that for violet light. \(\frac{1}{f} = (\mu - 1)\left( {\frac{1}{{{R_1}}} - \frac{1}{{{R_2}}}} \right)\) \({\mu _R} < {\mu _V}\) So correct option is (1).
PHXII09:RAY OPTICS AND OPTICAL INSTRUMENTS
364824
A convex lens of crown glass \(\left( {n = 1.525} \right)\) will behave as a divergent lens if immersed in
1 In a medium of \(\left( {n = 1.33} \right)\)
2 Water \(\left( {n = 1.33} \right)\)
3 It cannot act as a divergent lens
4 Carbon disulphide \(n = 1.66\)
Explanation:
A lens shows opposite behaviour if \({\mu _{medium}} > {\mu _{lens}}\)
