Questions
Question 1
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What two conditions are required for total internal reflection?
Question 2
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State the critical angle formula for light going from \(n_1\) to \(n_2\), where \(n_1>n_2\).
Question 3
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Find the critical angle for glass \((n=1.50)\) to air \((n=1.00)\).
Question 4
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Light in glass \((n=1.50)\) reaches an air boundary at \(50^\circ\). Does total internal reflection occur?
Question 5
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Light travels from water \((n=1.33)\) to air. Find the critical angle.
Question 6
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Can total internal reflection occur when light travels from air into glass? Explain.
Question 7
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At the critical angle, what is the refracted angle?
Question 8
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A transparent material has critical angle \(35.0^\circ\) at an air boundary. Find its refractive index.
Question 9
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Derive the critical angle formula from Snell's law.
Question 10
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An optical fiber core has \(n=1.48\) and cladding has \(n=1.46\). Find the critical angle at the core-cladding boundary and explain why the angle is large.
Question 11
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Diamond has \(n=2.42\). Find its critical angle at a diamond-air boundary.
Question 12
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A ray inside glass \((n=1.50)\) hits a glass-air boundary at \(40^\circ\). Does it refract or totally internally reflect?
Question 13
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For glass \((n=1.50)\) to air, find the refracted angle when the incident angle is \(40^\circ\).
Question 14
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A material has critical angle \(60^\circ\) at an air boundary. Find its refractive index.
Question 15
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A ray travels inside a fiber core \((n=1.50)\) surrounded by cladding \((n=1.45)\). The ray makes \(12^\circ\) with the fiber axis. Assuming the wall is parallel to the axis, does it totally internally reflect at the core-cladding boundary?
Question 16
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Derive the largest ray angle to the fiber axis for total internal reflection inside a straight fiber with core index \(n_1\) and cladding index \(n_2\).
Question 17
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For a fiber with \(n_1=1.50\) and \(n_2=1.45\), find the largest internal ray angle to the fiber axis that still totally internally reflects.
Question 18
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Use Snell's law to show why no real refracted angle exists beyond the critical angle.
Question 19
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A glass prism in air is used so a ray inside the prism hits a face at \(45^\circ\). If the glass has \(n=1.52\), determine whether total internal reflection occurs.
Question 20
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Explain why total internal reflection can be nearly lossless even though ordinary reflection from glass can be weak.