A) \[{{35}^{o}}\]
B) \[{{55}^{o}}\]
C) \[{{50}^{o}}\]
D) \[{{70}^{o}}\]
Correct Answer: C
Solution :
A ray of light incident on mirror P at an angle \[={{55}^{o}}\] \[\therefore \] \[\angle i=90-{{55}^{o}}={{35}^{o}}\] \[\therefore \] \[\angle r=\angle i={{35}^{o}}\] Hence \[\angle B={{180}^{o}}-({{55}^{o}}+{{35}^{o}}+{{35}^{o}})\] \[={{180}^{o}}-{{125}^{o}}={{55}^{o}}\] \[\therefore \] \[\angle C={{180}^{o}}-({{60}^{o}}+{{55}^{o}})={{180}^{o}}-{{115}^{o}}={{65}^{o}}\] \[\therefore \] \[\angle A=2[{{90}^{o}}-{{65}^{o}}]=2[{{25}^{o}}]={{50}^{o}}\]You need to login to perform this action.
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