JEE Advanced 2013Paper 1
- Exam
- JEE Advanced
- Year
- 2013
- Paper
- Paper 1
- Subject
- Physics
- Chapter
- Ray Optics
JEE Advanced 2013 · Paper 1 · Physics · Ray Optics
A ray of light, travelling in the direction (1)/(2)( ^ i + 3 ^ j )...
A ray of light, travelling in the direction \dfrac{1}{2}\left(\overset{^}{i} + \sqrt{3}\overset{^}{j}\right), is incident on a plane mirror. After reflection, it travels along the direction \dfrac{1}{2}\left(\overset{^}{i} - \sqrt{3}\overset{^}{j}\right). The angle of incidence is
Options
- A
- B
- C
- D
Correct answer
A.
Step-by-step solution
= angle between vectors
\text\cos\alpha = \dfrac{\dfrac{1}{2}\left(\overset{^}{\text{i}} + \sqrt{3}\overset{^}{\text{j}}\right) \cdot \dfrac{1}{2}\left(\overset{^}{\text{i}} - \sqrt{3}\overset{^}{\text{j}}\right)}{\left|\overset{^}{\text{i}} + \sqrt{3}\overset{^}{\text{j}}\right|\left|\overset{^}{\text{i}} - \sqrt{3}\overset{^}{\text{j}}\right|}
\text\cos\alpha = \dfrac{\dfrac{1}{2}\left(\overset{^}{\text{i}} + \sqrt{3}\overset{^}{\text{j}}\right) \cdot \dfrac{1}{2}\left(\overset{^}{\text{i}} - \sqrt{3}\overset{^}{\text{j}}\right)}{\left|\overset{^}{\text{i}} + \sqrt{3}\overset{^}{\text{j}}\right|\left|\overset{^}{\text{i}} - \sqrt{3}\overset{^}{\text{j}}\right|}