{"id":87965,"date":"2025-06-01T06:58:45","date_gmt":"2025-06-01T06:58:45","guid":{"rendered":"https:\/\/exam.pscnotes.com\/mcq\/?p=87965"},"modified":"2025-06-01T06:58:45","modified_gmt":"2025-06-01T06:58:45","slug":"shown-in-the-figure-are-two-plane-mirrors-xy-and-yz-xy-%e2%8a%a5-yz-joined-a","status":"publish","type":"post","link":"https:\/\/exam.pscnotes.com\/mcq\/shown-in-the-figure-are-two-plane-mirrors-xy-and-yz-xy-%e2%8a%a5-yz-joined-a\/","title":{"rendered":"Shown in the figure are two plane mirrors XY and YZ (XY \u22a5 YZ) joined a"},"content":{"rendered":"

Shown in the figure are two plane mirrors XY and YZ (XY \u22a5 YZ) joined at their edge. Also shown is a light ray falling on one of the mirrors and reflected back parallel to its original path as a result of this arrangement. The two mirrors are now rotated by an angle \u03b8 to their new position X’Y’Z’, as shown. As a result the new reflected ray is at an angle \u03b1 from the original reflected ray. Then :<\/p>\n

[amp_mcq option1=”\u03b1 = 0″ option2=”\u03b1 = \u03b8” option3=”\u03b1 = 2\u03b8” option4=”\u03b1 = 4\u03b8” correct=”option1″]<\/p>\n

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This question was previously asked in<\/div>\n
UPSC NDA-1 – 2023<\/div>\n<\/div>\n
Download PDF<\/a>Attempt Online<\/a><\/div>\n<\/div>\n
For a ray of light reflecting successively from two plane mirrors placed perpendicular to each other, the final reflected ray is always anti-parallel to the incident ray, regardless of the initial angle of incidence.<\/section>\n
This property is characteristic of a corner reflector made of two perpendicular mirrors. The total deviation after two reflections is 180 degrees. When the mirrors are rotated together by an angle \u03b8, the angle between them remains 90 degrees. Therefore, the property holds true, and the final reflected ray remains anti-parallel to the incident ray.<\/section>\n
Since the original reflected ray is anti-parallel to the incident ray and the new reflected ray is also anti-parallel to the *same* incident ray, the two reflected rays are parallel to each other and in the same direction (anti-parallel to the incident ray). The angle between them, \u03b1, is 0.<\/section>\n","protected":false},"excerpt":{"rendered":"

Shown in the figure are two plane mirrors XY and YZ (XY \u22a5 YZ) joined at their edge. Also shown is a light ray falling on one of the mirrors and reflected back parallel to its original path as a result of this arrangement. The two mirrors are now rotated by an angle \u03b8 to … <\/p>\n

Detailed SolutionShown in the figure are two plane mirrors XY and YZ (XY \u22a5 YZ) joined a<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1093],"tags":[1105,1153,1128],"class_list":["post-87965","post","type-post","status-publish","format-standard","hentry","category-upsc-nda-1","tag-1105","tag-optics","tag-physics","no-featured-image-padding"],"yoast_head":"\nShown in the figure are two plane mirrors XY and YZ (XY \u22a5 YZ) joined a<\/title>\n<meta name=\"description\" content=\"For a ray of light reflecting successively from two plane mirrors placed perpendicular to each other, the final reflected ray is always anti-parallel to the incident ray, regardless of the initial angle of incidence. This property is characteristic of a corner reflector made of two perpendicular mirrors. The total deviation after two reflections is 180 degrees. When the mirrors are rotated together by an angle \u03b8, the angle between them remains 90 degrees. 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