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This is one of our many quizzes on Reflection. Click on this to access more such competitive quizzes on SHM Waves and Optics.

Reflection Quiz 2

physics

 The angle of incidence for the given ray diagram is, $ \\ $ <img  src="https://cmds-vedantu.s3.ap-southeast-1.amazonaws.com/prod/question-sets/1adf5764-4a66-44ab-b8c7-6ade297a964f1764522354982477874.png"/> 

The key point to remember are the arrow marks of the given ray diagram. If the ray points the surface, then, it represents the incident ray and if the ray does not point to the surface, then, it represents the reflected ray. The angle of incidence is measured along the normal. 

 The angle of incidence equals the angle of reflection. $ \\ $ By considering the value of angle given in the figure. The angle of reflection is, $ \\ r+43{}^\circ =90{}^\circ  \\ \Rightarrow r=90{}^\circ -43{}^\circ  \\ \Rightarrow r=47{}^\circ\\ $ Hence, the value of angle of incidence is $\\ i=r \\ \therefore i=47{}^\circ$ 

The angle of reflection for the given ray diagram is, $ \\ $ <img  src="https://cmds-vedantu.s3.ap-southeast-1.amazonaws.com/prod/question-sets/28acc800-af49-4c31-a9be-9c6c671cfdc43295661151969300916.png"/>

When the source travels from the denser medium to the rarer medium, in the case of water-air interface, the angle of incidence is less than the angle of refraction, as the refractive index of water is more than that of the air.  

 In the case of water air interface, the angle of incidence is less than the angle of refraction, as the refractive index of water is more than that of the air. $ \\ {{n}_{w}}>{{n}_{a}} \\ \Rightarrow {{\theta }_{incidence}} < {{\theta }_{refraction}} \\ $ The angle of incidence equals the angle of reflection. In the given options, only one angle is less than the angle of refraction.

The angle of reflection is, $ \\ $ <img  src="https://cmds-vedantu.s3.ap-southeast-1.amazonaws.com/prod/question-sets/7ba2e5ea-62d0-4d2b-bd50-632f11a1a16a6777756159022397362.png"/> 

 The diagram represents the angle of incidence and according to the law of reflection, the angle of incidence equals the angle of reflection. So, using this law, we will find the angle of incidence.  

The law of reflection states that the angle of incidence equals the angle of reflection. Thus, the angle of reflection equals the angle made by the reflecting ray with the normal of the plane. From the figure it’s clear that the angle of incidence is, $45{}^\circ $. Thus, the angle of reflection equals $45{}^\circ $.

Consider the figure. The angle of reflection is, $ \\ $ <img  src="https://cmds-vedantu.s3.ap-southeast-1.amazonaws.com/prod/question-sets/f51e86e0-6571-4da8-871c-6ae0153da70b1919618956161032429.png"/> 

The sum of the angle of incidence and the glancing angle equals $90{}^\circ $. So, using this, and the law of reflection we will find the angle of reflection. 

The angle of incidence is, $ \\ i=90{}^\circ -g \\  \Rightarrow i=90{}^\circ -15{}^\circ  \\ \therefore i=75{}^\circ  \\ $ The angle of incidence equals the angle of reflection. Therefore, the angle of reflection is, $ 75{}^\circ$.

 After reflection, the angle between the plane of the medium and the incident ray is $20{}^\circ $, then, the angle of deviation is,  

The sum of angle of incidence and the glancing angle equals $90{}^\circ $. After reflection, the angle of deviation equals half the value of the angle of incidence. 

The angle between the plane of the medium and the incident ray is called the glancing angle. $ \\ $ The incident angle is, $i+g=90{}^\circ $ $ \\ \Rightarrow i+20{}^\circ =90{}^\circ  \\  \Rightarrow i=70{}^\circ  \\ $ The angle of deviation is, $ \\  \delta =\dfrac{i}{2} \\ \Rightarrow \delta =\dfrac{70{}^\circ }{2} \\  \therefore\delta =35{}^\circ$