So, it forms a virtual image. Answer: The imaginary line passing through the pole and the principal focus of the spherical mirror is called its principal axis. Same effect can also be obtained from the other surface also. This was done by using an optics track with a mounted light and displayed image, and measurement of the location of image in full focus after movement of a white display plate set up after the lens system. In the presence of your instructor, place the lens on to the optical bench and observe the clarity of your image. While a ray diagram may help one determine the approximate location and size of the image, it will not provide numerical information about image distance and object size.
Determine the image distance and the image size. Question 11: Suppose two spherical mirrors with reflecting surface towards your face are lying on the table. A pin of length 2. Societies have a tendency to have distinct habits that their people live by, First, education is one example. The rays coming from the distant tree are parallel to each other and therefore, its image is formed at the principal focus of the convex lens.
We can infer from the figure that a clear and bright image could be obtained if the distant object a tree , is illuminated with sunlight and the screen is placed in the shade. Answer: The centre of the hollow sphere of which spherical mirror is a part is called the centre of curvature. Answer: Lens forms the image by refracting light. Question 24: For finding the focal length of a concave mirror, where do we keep the object? Answer: It depends on its focal length. Answer: Yes, it forms virtual image only when placed between focus and optical centre and for all other positions it forms real image. Good YouTube Video from Edunovas.
Question 40: Two plane mirrors are placed opposite to each other and a candle is placed in between, the image formed will be: a real and infinite b virtual and infinite c real and magnified d virtual and diminished. Distances measured in the direction of the incident ray are positive and the distances measured in the direction opposite to that of the incident rays are negative. It is a fixed point inside the lens on its principal axis through which light ray passing undeviated. Question 3: The image formed by a mirror is always virtual. While shaving, we keep our face between the pole and focus of a concave mirror to obtain an erect and enlarged image of the face.
Question 14: If the object is at infinity where will the image be formed in case of concave mirror? Any image that is upright and located behind the mirror is considered to be a virtual image. For a given separation of the object and screen it will be found that there are two positions where a clearly focused image can be formed. Consequently the experiment was an overall success, the minor errors contained in the data did not affect the outcome of the experiment, which succeeded to locate the focal point of the mirror. Answer: Concave mirror is used by dentist and in solar cooker. Find the location and nature of the image if a point object is placed on the principal axis at a distance of a 9. Don't forget that you know the value of s o + s i.
Answer: Sun Question 3: What is the nature of an image formed by a thin convex lens for a distant object? Answer: The mirror which forms the virtual, erect and magnified image of our face is concave. From the calculations in the second example problem it can be concluded that if a 4. Question 10: What is radius of curvature of concave mirror? What is its focal length? To use a converging lens or convex lens as a magnifying glass, the object should be placed within its focus to get a magnified and erect image of the object as shown in the figure below: A convex lens of short focal length has a greater magnifying power in comparison to a convex lens of large focal length. If the lens both spherical surfaces is surrounded by the same medium having equal refractive indices, then the two principal focal lengths of the lens will be equal, i. Answer: The nature of image formed by the concave mirror is real and inverted for distant object. Question 20: A sharp image of a distant object is obtained on a screen using a convex lens.
Answer: When parallel rays of light fall on a concave mirror along its axis, then the rays meet at a point infront of the mirror after reflection from it. Apparatus : An optical bench with three upright central upright fixed , two outer uprights with lateral movements , a convex lens with lens holder , two optical needle , one thin , one thick a knitting needle and a half meter scale. If the shift of the object is 6 cm. Question 6: What is refraction? Question 20: How will you distinguish a concave lens from a convex lens experimentally? Question 6: What is focal length of a concave mirror? How will you distinguish between them just by looking? This expression is valid for concave as well as convex spherical mirrors. An approximate focal length was found using parallel light from a distant object. Explain giving reason whether it will behave as a converging lens or diverging lens in each of these two media.
The teacher then gave him another mirror of focal length, f 2 and asked him to obtain a focussed image of the same object on the same screen. For the refraction by spherical lens, we assume i Lens to be a thin lens having small thickness. To begin with, culture is the way a person was raised. It is denoted by C. In which case will the student get more accurate value of focal length? Several pairs of values of u and v are found and the results entered in a table as shown. Note the position of I. How will you distinguish between a concave and a convex mirror? Check by moving M close to L that the combination of M and L behaves as a concave mirror and you receive an inverted image of O.
The diameter of the lens is d. Question 5: If we cover one half of the convex lens while focussing a distant object, in what way will it affect the image formed? Magnification and sharpness of the image formed by a lens can be increased by combining a number of lenses. To obtain the position of image for a given object distance and focal length of a mirror, the following mirror formula can be used. In reflector type solar cookers, special concave parabolic mirrors are used. Answer: When the light rays travelling obliquely from one medium to another, a change in the direction of propagation in the second medium is observed.