**The refractive index of the medium M in the diagram above is**

**A. 2/√3**

**B. √3**

**C. 1/√3**

**D. √3/2**

**QUICK ANSWER…**

**B**

**DETAILS…**

**Refractive index of a medium is the ratio of the sine of angle of incidence to the sine of angle of refraction as light ray travels from space to the medium.**

**Mathematically,**

**Refractive index **= **sine i / sine r**

**Angle of incidence will be the angle the incident ray makes with the vertical line (also called the normal) =****60°****Angle of refraction will be the angle the refracted ray makes with the vertical = (90 – 60) =****30°**

**Now for the right answer to the above question:**

**Option A is incorrect.****Option B is correct.****C is incorrect.****D is not the correct answer.**

**KEY POINTS…**

**You may please note these/this:**

**Angle of incidence will be the angle the incident ray makes with the vertical line (also called the normal), and not the horizontal line. this angle of incidence = 60 degrees.****Angle of refraction will be the angle the refracted ray makes with the vertical = (90 – 60) = 30 degrees.****Refractive index of air can also be calculated by inverting that of the medium.**

**YOU CAN ADD YOUR OWN ANSWERS BELOW OR USE THE GOLDEN ‘ASK A QUESTION BOTTON’ DOWN THIS PAGE TO RAISE NEW RELATED QUESTIONS… OUR COMMUNITY OF EXPERTS WILL BE HAPPY TO TACKLE IT…**

**/ culled from 2016 JAMB-UTME physics past question 16 /**