जब कोई वस्तु दो समानांतर समतल दर्पणों के बीच रखी जाती है, तो बनने वाले प्रतिबिम्बों की संख्या कितनी होती 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?