Optics 2 Question 7
7. A ray of light travelling in water is incident on its surface open to air. The angle of incidence is $\theta$, which is less than the critical angle. Then there will be
(2007, 3M)
(a) only a reflected ray and no refracted ray
(b) only a refracted ray and no reflected ray
(c) a reflected ray and a refracted ray and the angle between them would be less than $180^{\circ}-2 \theta$
(d) a reflected ray and a refracted ray and the angle between them would be greater than $180^{\circ}-2 \theta$
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Answer:
Correct Answer: 7. (c)
Solution:
- Since $\theta<\theta _c$, both reflection and refraction will take place. From the figure we can see that angle between reflected and refracted rays $\alpha$ is less than $180^{\circ}-2 \theta$.
