A man who is 6.0 feet tall wishes to install a mirror on his wall so that he can see all of his body length, but no more. After many rough sketches, he concludes that the mirror should be approximately...?
7 years ago
Answered By Alexandria M
This is a question that only requires a diagram, similar to the one drawn below. r is the required height of the mirror. To draw the diagram one needs to use the law of reflection (that is the angle the light ray hits the mirror at is equal to the angle it reflects at(see LR diagram)) and draw it so the reflected rays approximatley hit where the eyes are. Use a constant scale in your diagram(ie 1cm=1ft, or 1 inch=1ft), use a ruler to measure r, and convert it back. So long as the angles are about right, you'll get a good approximation, which is about 3ft (ie half his height)
In order to solve this problem , we need to understand the concept of Geometrical Optics , specifically the Reflection of Light .
So in this the mirror needs to be 3 ft . Half of the heigth of the man
7 years ago
Answered By Victor A
Ray diagrams can be used to determine where a person must sight along a mirror in order to see an image of him. Therefore, ray diagrams can be used to determine what portion of a plane mirror must be used in order to view an image. The diagram shown by tutor Alexandria M (who provided an answer) depicts a tall man standing in front of a plane mirror. To see the image of his feet, he must sight along a line towards his feet; and to see the image of the top of his head, he must sight along a line towards the top of his head. The ray diagram depicts these lines of sight and the complete path of light from his extremities to the mirror and to the eye. In order to view his image, the man must look as low as point Y (to see his feet) and as high as point X (to see the tip of his head). The man only needs the portion of mirror extending between points X and Y in order to view his entire image. All other portions of the mirror are useless to the task of this man viewing his own image. I hope this comment and my colleague’s comments help to find the answer the student is looking for.
7 years ago
Answered By Alexandria M
This is a question that only requires a diagram, similar to the one drawn below. r is the required height of the mirror. To draw the diagram one needs to use the law of reflection (that is the angle the light ray hits the mirror at is equal to the angle it reflects at(see LR diagram)) and draw it so the reflected rays approximatley hit where the eyes are. Use a constant scale in your diagram(ie 1cm=1ft, or 1 inch=1ft), use a ruler to measure r, and convert it back. So long as the angles are about right, you'll get a good approximation, which is about 3ft (ie half his height)
Attached Whiteboard:
Play Drawing7 years ago
Answered By Sosimo H
In order to solve this problem , we need to understand the concept of Geometrical Optics , specifically the Reflection of Light .
So in this the mirror needs to be 3 ft . Half of the heigth of the man
7 years ago
Answered By Victor A
Ray diagrams can be used to determine where a person must sight along a mirror in order to see an image of him. Therefore, ray diagrams can be used to determine what portion of a plane mirror must be used in order to view an image. The diagram shown by tutor Alexandria M (who provided an answer) depicts a tall man standing in front of a plane mirror. To see the image of his feet, he must sight along a line towards his feet; and to see the image of the top of his head, he must sight along a line towards the top of his head. The ray diagram depicts these lines of sight and the complete path of light from his extremities to the mirror and to the eye. In order to view his image, the man must look as low as point Y (to see his feet) and as high as point X (to see the tip of his head). The man only needs the portion of mirror extending between points X and Y in order to view his entire image. All other portions of the mirror are useless to the task of this man viewing his own image. I hope this comment and my colleague’s comments help to find the answer the student is looking for.