Rules for Drawing Plane Mirror Ray Diagrams

Ray Diagrams

The line of sight principle suggests that in order to view an image of an object in a mirror, a person must sight along a line at the image of the object. When sighting along such a line, lite from the object reflects off the mirror according to the law of reflection and travels to the person'southward eye. This procedure was discussed and explained before in this lesson. One useful tool that is frequently used to depict this idea is known as a ray diagram. A ray diagram is a diagram that traces the path that low-cal takes in order for a person to view a point on the image of an object. On the diagram, rays (lines with arrows) are drawn for the incident ray and the reflected ray. Complex objects such equally people are often represented past stick figures or arrows. In such cases it is customary to draw rays for the extreme positions of such objects.

Drawing Ray Diagrams - a Step-past-Step Approach

This section of Lesson 2 details and illustrates the procedure for drawing ray diagrams. Allow's begin with the task of cartoon a ray diagram to show how Suzie volition be able to see the prototype of the light-green object arrow in the diagram below. For simplicity sake, nosotros will suppose that Suzie is viewing the image with her left eye closed. Thus, nosotros volition focus on how light travels from the two extremities of the object pointer (the left and right side) to the mirror and finally to Suzie's right eye as she sights at the image. The four steps of the procedure for cartoon a ray diagram are listed, described and illustrated beneath.

1. Draw the image of the object.

Use the principle that the object distance is equal to the image altitude to make up one's mind the exact location of the object. Option one extreme on the object and carefully measure the distance from this farthermost point to the mirror. Mark off the same distance on the opposite side of the mirror and mark the image of this extreme point. Echo this procedure for all extremes on the object until y'all have adamant the consummate location and shape of the image. Note that all altitude measurements should be fabricated by measuring forth a segment that is perpendicular to the mirror.

two. Option i extreme on the image of the object and draw the reflected ray that will travel to the centre as it sights at this signal.

Use the line of sight principle: the heart must sight along a line at the image of the object in social club to run across the image of the object. It is customary to describe a bold line for the reflected ray (from the mirror to the center) and a dashed line as an extension of this reflected ray; the dashed line extends behind the mirror to the location of the image point. The reflected ray should have an arrowhead upon it to betoken the direction that the light is traveling. The arrowhead should be pointing towards the eye since the low-cal is traveling from the mirror to the eye, thus enabling the heart to see the image.

3. Draw the incident ray for lite traveling from the corresponding extreme on the object to the mirror.

The incident ray reflects at the mirror'southward surface co-ordinate to the law of reflection. But rather than measuring angles, yous can merely draw the incident ray from the farthermost of the object to the betoken of incidence on the mirror's surface. Since y'all drew the reflected ray in step 2, the signal of incidence has already been determined; the point of incidence is merely the bespeak where the line of sight intersects the mirror'southward surface. Thus draw the incident ray from the extreme indicate to the signal of incidence. One time more than, be certain to draw an arrowhead upon the ray to indicate its direction of travel. The arrowhead should be pointing towards the mirror since light travels from the object to the mirror.

four. Repeat steps 2 and 3 for all other extremities on the object.

After completing steps 2 and iii, y'all have merely shown how light travels from a unmarried extreme on the object to the mirror and finally to the eye. You will besides have to show how lite travels from the other extremes on the object to the eye. This is just a affair of repeating steps two and 3 for each individual extreme. Once repeated for each farthermost, your ray diagram is complete.

Your Plough to Practice

The best manner to learn to depict ray diagrams involves trying information technology yourself. It's easy. Merely duplicate the two setups below onto a bare sail of newspaper, take hold of a ruler/straightedge, and brainstorm. If necessary, refer to the four-step procedure listed above. When finished, compare your diagram with the completed diagrams at the bottom of this page.

Uses of Ray Diagrams

Ray diagrams can be particularly useful for determining and explaining why just a portion of the image of an object can be seen from a given location. The ray diagram at the right shows the lines of sight used by the eye in order to see a portion of the paradigm in the mirror. Since the mirror is not long enough, the eye can only view the topmost portion of the paradigm. The lowest point on the epitome that the eye can see is that signal in line with the line of sight that intersects the very bottom of the mirror. As the eye tries to view even lower points on the paradigm, there is not sufficient mirror present to reverberate light from the lower points on the object to the eye. The portion of the object that cannot exist seen in the mirror is shaded light-green in the diagram below.

Similarly, ray diagrams are useful tools for determining and explaining what objects might be viewed when sighting into a mirror from a given location. For instance, suppose that half-dozen students - Al, Bo, Cy, Di, Ed, and Fred sit in front of a aeroplane mirror and endeavor to run into each other in the mirror. And suppose the exercise involves answering the following questions: Whom tin Al see? Whom can Bo see? Whom can Cy see? Whom can Di run across? Whom tin Ed see? And whom tin Fred come across?

The job begins by locating the images of the given students. Then, Al is isolated from the rest of the students and lines of sight are fatigued to see who Al can see. The leftward-most student whom Al can see is the student whose prototype is to the right of the line of sight that intersects the left edge of the mirror. This would be Ed. The rightward-most student who Al tin can see is the student whose paradigm is to the left of the line of sight that intersects the right edge of the mirror. This would be Fred. Al could see whatever pupil positioned between Ed and Fred by looking at whatever other positions along the mirror. Withal in this case, at that place are no other students betwixt Ed and Fred; thus, Ed and Fred are the merely students whom Al tin see? The diagram below illustrates this using lines of sight for Al.

Of course the same procedure can be repeated for the other students past observing their lines of sight. Possibly yous will want to try to determine whom Bo, Cy, Di, Ed, and Fred can come across? Then check your answers by clicking the button beneath.

Cheque Your Understanding

1. 6 students are arranged in front of a mirror. Their positions are shown beneath. The paradigm of each student is also drawn on the diagram. Brand the appropriate line of sight constructions to decide that students each individual educatee tin meet.

 

Hither are completed diagrams for the two examples given in a higher place in the Your Plough to Practice section.

Back to Diagram.

huiefoughted2000.blogspot.com

Source: https://www.physicsclassroom.com/class/refln/Lesson-2/Ray-Diagrams-for-Plane-Mirrors

Share this post