Q. No.The speed of light in media and is and respectively. A ray of light enters from medium to at an incidence angle i. If the ray suffers total internal reflection, the value of i is:
| 1. | equal to \(\sin ^{-1}\left(\frac{2}{3}\right)\) |
| 2. | equal to or less than \(\sin ^{-1}\left(\frac{3}{5}\right)\) |
| 3. | equal to or greater than \(\sin ^{-1}\left(\frac{3}{4}\right)\) |
| 4. | less than \(\sin ^{-1}\left(\frac{2}{3}\right)\) |
The ratio of the velocity of light in a medium to the velocity of light in a vacuum is \(\frac{4}{5}\). If the ray of light is emerging from this medium into the air, then the critical angle for this interface of medium and air will be:
| 1. | \(30^\circ\) | 2. | \(37^\circ\) |
| 3. | \(53^\circ\) | 4. | \(45^\circ\) |
A rainbow is formed due to:
| 1. | Scattering & refraction |
| 2. | Total internal reflection & dispersion |
| 3. | Reflection only |
| 4. | Diffraction and dispersion |
Light enters at an angle of incidence in a transparent rod of refractive index n. For what value of the refractive index of the material of the rod, will the light, once entered into it, not leave it through its lateral face whatsoever be the value of the angle of incidence?
1.
2. 1.0
3. 1.3
4. 1.4
In total internal reflection when the angle of incidence is equal to the critical angle for the pair of media in contact, what will be the angle of refraction?
| 1. | \(90^{\circ}\) |
| 2. | \(180^{\circ}\) |
| 3. | \(0^{\circ}\) |
| 4. | equal to the angle of incidence |
| Assertion (A): | Critical angle of light passing from angle to air is minimum for violet colour. |
| Reason (R): | The wavelength of violet light is greater than the light of other colours. |
| 1. | Both (A) and (R) are true and (R) is the correct explanation of (A). |
| 2. | Both (A) and (R) are true but (R) is not the correct explanation of (A). |
| 3. | (A) is true but (R) is false. |
| 4. | Both (A) and (R) are false. |
| 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 travelling from an optically rarer to a 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. |
If \(C_1,~C_2 ~\mathrm{and}~C_3\) are the critical angle of glass-air interface for red, violet and yellow color, then:
| 1. | \(C_3>C_2>C_1\) | 2. | \(C_1>C_2>C_3\) |
| 3. | \(C_1=C_2=C_3\) | 4. | \(C_1>C_3>C_2\) |
A fish is a little away below the surface of a lake. If the critical angle is \(49^{\circ}\), then the fish could see things above the water surface within an angular range of \(\theta^{\circ}\) where:
1. \(\theta = 49^{\circ}\)
2. \(\theta = 90^{\circ}\)
3. \(\theta = 98^{\circ}\)
4. \(\theta = 24\frac{1}{2}^{\circ}\)
A small coin is resting on the bottom of a beaker filled with a liquid. A ray of light from the coin travels up, to the surface of the liquid and moves along its surface (see figure).
How fast is the light traveling in the liquid?
| 1. | \(1.8 \times 10^8 \mathrm{~m} / \mathrm{s} \) | 2. | \(2.4 \times 10^8 \mathrm{~m} / \mathrm{s} \) |
| 3. | \(3.0 \times 10^8 \mathrm{~m} / \mathrm{s} \) | 4. | \(1.2 \times 10^8 \mathrm{~m} / \mathrm{s}\) |
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