A given ray of light suffers minimum deviation in an equilateral prism P. Additional prisms Q and R of identical shape and of same material as that of $\mathrm{P}$ are now combined as shown in figure. The ray will now suffer

• A

  greater deviation
• B

  no deviation
• Correct answer
  C

  same deviation as before
• D

  total internal reflection

Solution

When the ray suffers minimum deviation, it becomes parallel to the base of prism P. As prisms $\mathrm{Q}$ and $\mathrm{R}$ are of same material and have identical shape, therefore, the ray continues to be parallel to base of $Q$ and $R$. Hence final deviation of the ray remains the same as before.

Hence, the correct answer is option: 'C'.