Q2,let us say we have a 10X magnifying glass. I am estimating that the focal length would be about 2 in. I think that the magnifying mirror that you are talking about is just a magnifying glass.

Q3,d

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Q1,When you see a cat is playing in the back yard , the distance from your eye to a cat is called the focal length

Q2,

Q3,c

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Q1,In myown words I would say that a focal length is the length of a ray when it is reflected off of a mirror and it converges with other rays reflected from the same mirror.

Q2,Choosing a mirror w/ radius of curvature 5 in. the focal length is 2.5 inches.

Q3,b

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Q1,without even looking at the book i realized it had something to do with (at least similarly) the part that sticks out from the center of a satellite dish.

Q2,if it were an entire sphere, then the radius would be (guessing) 1 meter. In that case, it would be 1/2 meter.

Q3,d

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Q1,The focal length is the distance from the edge of the mirror to the point where the rays converge and focus.

Q2,If the mirror had a radius of curvatur of 5 cm, then the focal length would be 2.5 cm.

Q3,d

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Q1,The focal length is the distance from the vertex to the poin where incident parallel rays converge or the distance where rays diverging from the same point F are parallel to the axis of reflection.

Q2,Assuming the radius is 5cm, the focal length f=2.5cm.

Q3,d

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Q1,It is kind of a dividing point that determines what kind of image you will get. Also, it is a 'focus' point for rays of light on either side of a ' ' that changes the direction of those light rays

Q2,1/f=1/s+1/s(prime) For the sake of estimation, I would say that a 'cosmetic mirror' might double the size of my face. also, it seems to work best at about .15m also, I think you can use y and y' somewhat interchangeably. 1/f=1/1+1/2 1/f=3/2 (with s) f=2/3m estimate

Q3,a

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Q1,The distance to the surface of reflection from the point that is the source for that reflection. It is always a distance and always represented as being from the mirror.

Q2,The focal length of a typical mirror is infinite.

Q3,d

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Q1,The distance from the center of the lens to where the light rays converge.

Q2,for a mirror with radius 5cm, f=5/2

Q3,a

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Q1,The focal length is the distance from the vertex to the focal point of the mirror/lens. So it is the distance from the mirror where all the incident rays converge and are brought to focus

Q2,

Q3,d

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Q1,focal length is the distance between the point at which rays coverge to the vertex of the item.

Q2,f = r/2 1 cm/2 .5 cm

Q3,a

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Q1,The focal length is the length from the vertex of a parabola to the focas point.

Q2,f=R/2 f=.05 meters/2 f=.25

Q3,d

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Q1,Focal length is the distance from the vertex of a parabola to the focal point of a parabola.

Q2,f=R/2 f=.05meters/2 f=.25

Q3,d

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Q1,The focal lenght is the distance it tkaes for an object to reflect or refract as an image.

Q2,I thnk it would be about 3.5cm.

Q3,d

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Q1,The focal length is the distance from where a wave of light hits shot from focal point hits mirror surface and the ray will return on the same route.

Q2,I don't really know if there is an equation to use, but I estimate the focal length as being something like .5 meters.

Q3,a

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Q1,It's the distance from the edge of a reflecting surface to a point where all light reflected from that surface come together at the exact same spot, which is normally called the focal point or point of focus.

Q2,I would say since the mirror is usually about 5inches across and has a barely perceivable convex curve to it, the radius would probably be kind of large. So if I use 36 inches as my radius and divide it by 2 that gives me focal length of about 18 inches or 27 cm.

Q3,a

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Q1,The focal length is the distance from the vertex to the point at which the incident parallel rays converge.

Q2,If the radius of curvature of the mirror is 20 cm then the focal length of the mirror is 10cm. f=R/2

Q3,a

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Q1,The focal length is the distance from the mirror at which the focal point occurs. The focal point is where the incident rays converge or diverge.

Q2,If the mirror is a 2x magnifier then the focal length would be 0.5 m.

Q3,b

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Q1,the distance away from the image that is being seen.

Q2,R=4inches f=R/2=2inches

Q3,b

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Q1,I believe a focal length to be the distance from whatever reflecting surface(sattelite dish or concave mirror...etc.) to the point where all reflected beams or waves meet.

Q2,Well, lets say our mirror magnifies 2:1. Well, the focal length is 1/6ft + 1/12ft = 1/f (focal length). this gives us that f = 4ft

Q3,a

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Q1, The focal length is the distance away from a mirror when the object being reflected comes into focus.

Q2, If the R or radius of curvature is 10cm then using f=R/2, the focal lenght would be .05 meters.

Q3,d

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Q1,A focal length measures the distance between the focal point and the mirror/lens.

Q2,Let's say I want to look at my face in the mirror. I hold the mirror about ten centimeters from my face. The focal point is somewhere behind me (or maybe within my big head). So a good estimate of the focal length of the mirror would be about twenty centimeters.

Q3,d

Comments,Cool picture of a person in a mirror. If you were actually looking at this, and saw that image, you would have to be standing up and to the right to see the image in the mirror. :)

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Q1,focal lenght is the image that can be seen relative to the distance of the image and the determining viewpoint.

Q2,if the mirror is say 6 inches round; the focal length would be approximately 0.4

Q3,d

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Q1,The focal length is the distance from the surface of a spherical, reflecting surface to the point where reflected rays converge. The point where the reflected image looks 'in focus'.

Q2,About 6' to 10'.

Q3,d

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Q1,When horizontal beam of light hit parabolic mirrors, the reflected beams would all go through the same point which is called the focal point. The distance between the focal point and the point of the mirror where a beam of light goes through both when going toward the mirror and when reflected from the mirror is called the focal length.

Q2,Say that the lateral magnification is 5X. Then m = 5, and y'/y = 5. Say that the object is 10 cm behind the lens. Then 1/s-1/(5s)=1/f. f=5s/4, f = 12.5cm.

Q3,d

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Q1,The focal length will be that specific length from the surface of the reflecting object that will bring the image of the object into focus. If rays were to be reflected in front of or back of the focal point, we would see an out of focus image.

Q2,Focal length f is R/2. I have no idea what the radius of curvature would be but assume it is about 7 in. or 17.78 cm. The focal length would be 8.89 cm.

Q3,d

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Q1,Focal length is the distance or length too be in focus. A point of convergence.

Q2,6'

Q3,d

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Q1,Focal length is the distance from the focal point to the vertex of a curvature or the center of a lens. The focal point is a point where rays of light converge.

Q2,I think the focal length would be the distance you would be from the magnifying mirror and get the clearest image, about 20 cm.

Q3,d

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Q1,Focal length is defined as the distance from the vertex to the focal point. Focal length is defined as the distance from the focal plane to the center of the lens when focused at infinity.

Q2,Assume R = 7cm Focal length = 3.5 cm

Q3,d

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Q1,The focal point is the point which reflections or refractions of incoming parallel rays converge to, or appear to diverge from. The focal length is the perpendicular distance of this point from the surface of the mirror or lens.

Q2,Let us assume a given magnifying mirror produces a lateral magnificataion of 1.5 when held 0.1 m away. Since m = (yprime/y) = -(sprime/s) = 1.5, and s = 0.1 m, sprime = 0.15 m. We also know that (1/s) + (1/sprime) = (1/f). Therefore, f = 0.06 m.

Q3,d

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Q1,In a simple definition, focal length is the distance from the focal point to the vertex. Upon reading this one may be inclined to ask the definitions of the focal point and vertex. Simply put (perhaps too simply), the focal point is the point where the parallel rays from the reflection converge and the vertex is the center of the reflecting surface.

Q2,Hypothetically speaking if one were to have a 6 inch 'magnifying mirror' laying around his house and a 3 inch index finger on the end of his hand. One could measure the distance from his mirror to his finger at the point when the image of his finger appears to be as long as the mirror, this would mean the image height would be twice that of the object height. Let's say that the distance between the mirror and the finger, or object distance, is 18 inches. From equation 35-7 on page 1092 in the text, one could calculate that the image distance is 36 inches. Using equation 35-6 on page 1091 in the text, one could calculate the focal length to be 12 inches. Hypothetically speaking, of course.

Q3,b

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Q1,

Q2,

Q3,b

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Q1, The focal length is the length from an reflective object's vertex to a certain point called a focal point ( if it exists ) where all waves pass through when reflected off that object.

Q2,Assuming the wave source is at a great distance from the mirror, and the radius ( if it were a complete circle ) is 1/2 a meter. The focal length = R/2 = 1/4 meter.

Q3,d

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Q1,A focal lenght is the distance needed from someone's eye to a lense so that the object on the other side can be seen clearly. It appears that this distance is also the distance between the lense and the object.

Q2,About 1 foot.

Q3,d

Comments,Monday is April 6th. Nice stick figure, awesome nose, needs a few zits though.

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Q1,The focal length is the distance between two focal points. Depending on which side the rays of light are originating, the focal points are the points where the light rays cross. One focal points are eqidistant from the mirror.

Q2,Let's assume the mirror is a concave mirror. Therefore, the focal length of the 'spherical mirror' is the radius of curvature divided by 2. Let's take a look at the 'sphere'. I'll say that the S (arc length) is equal to 5 cm. Let's also say that it 'takes' 1 degree of rotation to make it from the bottom of the mirror to the top of the mirror. With these two numbers, the radius is 2.86 meters, which makes the focal length 1.43 meters.

Q3,a

Comments,Once again I made an assumption to answer these questions. They were arbitrary assumptions which are probably not anywhere close to the real thing. But I tried. For number three, the reason why I say that the focal length is undefined is because I can't think of any instance where all of the incident light converges to one point. But that doesn't mean that I am right.

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Q1,The focal length is the distance between two focal points. Depending on which side the rays of light are originating, the focal points are the points where the light rays cross. One focal points are eqidistant from the mirror.

Q2,Let's assume the mirror is a concave mirror. Therefore, the focal length of the 'spherical mirror' is the radius of curvature divided by 2. Let's take a look at the 'sphere'. I'll say that the S (arc length) is equal to 5 cm. Let's also say that it 'takes' 1 degree of rotation to make it from the bottom of the mirror to the top of the mirror. With these two numbers, the radius is 2.86 meters, which makes the focal length 1.43 meters.

Q3,a

Comments,Once again I made an assumption to answer these questions. They were arbitrary assumptions which are probably not anywhere close to the real thing. But I tried. For number three, the reason why I say that the focal length is undefined is because I can't think of any instance where all of the incident light converges to one point. But that doesn't mean that I am right.

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