Question

Two plane mirrors are at an angle of $30^{∘}.$ Find the deviation produced in the ray after 3 successive reflections as shown in figure.

• A. $80^{∘}$
• B. $30^{∘}$
• C. $40^{∘}$
• D. $50^{∘}$

Answer 1

Answer: (A)

${δ}_1=100^{∘}CW$
${δ}_2=180−20=160ACW$
${δ}_3=180−40CW=140^{∘}$
$δ=100^{∘}+140^{∘}−160^{∘}=80^{∘}$