पानी से भरे किसी बर्तन में पड़ा हुआ सिक्का किस प्रकाशीय परिघटना के कारण थोड़ा ऊपर उठा हुआ प्रतीत होता है?

A light ray incident on a plane mirror makes an angle of 30° with the mirror surface. What is the angle made by the reflected ray with the normal?

After refraction of a plane wave incident on a rarer medium, the wave front / ray ______.

What does the acronym LASER stand for in the context of light technology?