If two convex lenses of powers \(P_1,P_2\) be placed close together, co-axially, the combination behaves as a lens of power:
1. \(P_1+P_2\) 2. \(|P_1-P_2|\)
3. \({\Large\frac{P^2_1}{P_2}}\) 4. \({\Large\frac{P^2_2}{P_1}}\)

Subtopic:  Lenses |
 86%
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Two convex lenses \((L_1,L_2)\) of focal lengths, \(20\) cm \((L_1)\) and \(40\) cm \((L_2),\) are placed co-axially at a separation of \(60\) cm. If a parallel beam of light is incident on \(L_1,\) the emerging beam from \(L_2\)
1. is parallel but wider. 2. is parallel but narrower.
3. is convergent. 4. is divergent.
Subtopic:  Refraction at Curved Surface |
 56%
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A ray is incident normally onto the surface \(AB\) of the prism \((\angle A=30^\circ,\angle B=90^\circ).\) The refractive index of the material of the prism is \(\sqrt2.\) The deviation of this ray is:
   
1. \(30^\circ\) downward
2. \(15^\circ\) downward
3. \(30^\circ\) upward
4. \(15^\circ\) upward
Subtopic:  Prisms |
 69%
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A parallel beam of light is incident onto a converging lens \((L_1)\) of focal length \(20~\text{cm}.\) A second identical lens \((L_2)\) is to be placed behind \(L_1,\) coaxially, so that the emerging beam is parallel. The distance between \(L_1\) and \(L_2\) should be:
1. \(10\) cm 2. \(20\) cm
3. \(40\) cm 4. zero
Subtopic:  Lenses |
 76%
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Given below are two statements: 
Statement I: In total internal reflection, the angle of incidence must be greater than a certain minimum angle which depends on the media involved.
Statement II: Total internal reflection cannot occur when light is traveling from an optically rarer to an optically denser medium.
 
1. Statement I is incorrect and Statement II is correct.
2. Both Statement I and Statement II are correct.
3. Both Statement I and Statement II are incorrect.
4. Statement I is correct and Statement II is incorrect.
Subtopic:  Total Internal Reflection |
 75%
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Which, of the following, does not suffer from chromatic aberration?
1. convex lens
2. plano-convex lens
3. concave lens
4. concave mirror
Subtopic:  Lenses |
 79%
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A ray of light is incident on a mirror which is lying on the \(x\text-y\) plane. The reflected ray travels along the direction of the vector \(3\hat i-4\hat j+2\hat k.\) The incident ray must be along:
1. \(-3\hat i+4\hat j+2\hat k\) 2. \(3\hat i-4\hat j-2\hat k\)
3. \(-3\hat i-4\hat j+2\hat k\) 4. \(-3\hat i+4\hat j-2\hat k\)
Subtopic:  Reflection at Plane Surface |
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Two identical right-angled prisms are placed back to back as shown. A ray of light, incident on the first prism, making an angle \(\theta\) with its surface – passes through the system and emerges parallel to itself. The refractive index of the material of the prism is:
          
1. \(\sin\theta\)
2. \(\cos\theta\)
3. \(\tan\theta\)
4. \(\cot\theta\)
Subtopic:  Refraction at Plane Surface |
 51%
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As light traverses through an optical medium, it is observed that its wavelength decreases.
Statement I: In this case, the frequency of light increases.
Statement II: In the above case, the refractive index of the medium increases.
 
1. Statement I is incorrect and Statement II is correct.
2. Both Statement I and Statement II are correct.
3. Both Statement I and Statement II are incorrect.
4. Statement I is correct and Statement II is incorrect.
Subtopic:  Refraction at Plane Surface |
 65%
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A ray of light travelling in the air along the \(x\)-axis encounters a medium and the refracted ray is along \(\hat i+\sqrt3\hat j.\) The refractive index of the medium is:
1. less than or equal to \(2\)
2. greater than or equal to \(2\)
3. equals \(2\)
4. greater, less or equal to \(2\)
Subtopic:  Refraction at Plane Surface |
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