Tracy basked in the water, relishing the prickly fingers of hot water as it soothed the muscles of her body. Sharpness of focusing will be greatly assisted if a thin cross-wire is placed across the hole Fig. It isn't -44 cm since the negative sign would only correspond to an upright and virtual image. An object is placed at 20 cm from the pole of this lens. In order to get a sharp image on the screen, she will now need to move the screen a slightly nearer to the lens b slightly farther away from the lens c very close to the lens d very far away from the lens Question 4: If you are to determine the focal length of a convex lens, you should have a a convex lens and a screen.
Will it appear larger or smaller than its actual size and why? A Short Description about the Arrangement As a concave lens always forms a virtual image, its focal length can not be found directly as for a convex lens. The correct combination of mirrors is: a plane, convex and concave mirror b concave, plane, convex mirror c plane, concave and convex mirror d convex, concave and plane mirror. Answer: I am finding the focal length of a concave mirror by obtaining the image of a distant object. Question 12: Can this method be used to find the approximate focal length of a concave lens? Replace the pin I with mirror M. The top part is a concave mirror, the middle part is a plane miiTor and the bottom part is a convex mirror.
The surfaces are curved in same direction and of same radius Question. If the distance of the screen from the device is 30 cm, select the correct statement about the device X. Large aperture of concave mirror will cause spherical aberration. Arrange the screen on the table so that the image of the distant object is obtained on it. The solution is shown below. A thick cardboard white screen D.
How the power of lens charge w. Question 3: What will be the nature of image formed by a concave mirror for a distant object? To obtain the position of image for a given object distance and focal length of a lens, the following lens formula can be used. Question 3: The image formed by a mirror is always virtual. Answer: d Explanation: Convex lens converges all the rays and the distance between lens and focus is 40 cm. Answer: b Explanation: It is the distance between the focus and the mirror.
Finally, the image is a virtual image. In which case, will the student is closer to accurate value of focal length? Question 4: In reflector type solar cookers, special concave parabolic mirrors are used. Using knitting needle, adjust the object-pin, so that the distance between the pole of the mirror and the tip of the pin is l. Case 4: The object is located at F When the object is located at the focal point, no image is formed. Formation of Image If the parallel beam of light comes from a distant object, then a real, inverted image of very small size is formed at the focus of the lens as given in the Fig.
Be specific about the light bulb location. Question 5: The mirror used in solar cooker is a any spherical mirror b concave mirror c convex mirror d none of these Answer: b Explanation: All the rays after reflection meet at a point. For getting better results, the teacher suggested focussing of a distant tree instead of the grill. Concave mirror of large focal length is often used as shaving glass. If the image is magnified, the glass piece is a convex lens. When the image is focused, I will measure 'c' and also the magnification of the image. It is measured in term of speed of light in a medium w.
In which case will the student get more accurate value of focal length? His teacher remarked that for getting better value of focal length of the mirror he should focus a distant object preferably the sun on the screen. Question 25: The image formed by a plane mirror is always a real and erect b real and inverted c virtual and erect d virtual and inverted Answer: c Explanation: Plane mirror has virtual focus. Answer: In reflector type solar cooker, the position of food vessel should be at the focus of concave mirror. Question 2: What type of image is formed by a plane mirror? Question 3: What will be the nature of the image formed by a concave mirror for a distant object? Experiment: Find the focal length of a convex mirror using a convex lens. Regardless of exactly where the object is located, the image will be located in the specified region.
We wish to describe the characteristics of the image for any given object location. Give facts obtained from sign convention. A six-foot tall person would have an image that is six feet tall; the absolute value of the magnification is equal to 1. Explain giving reason whether it will behave as a converging lens or diverging lens in each of these two media. Get the focal length from all measurements by a taking average of calculated f or b from u versus v graph or c from versus graph.
For example If I understood your description correctly it suggest that a spherically concave mirror should form a virtual image on the other side of the mirror if the object is located at its focal point? An image needle I is put behind the convex lens and moved to a position at which there is no parallax between tip of inverted image of O needle and tip of I needle. For the refraction by spherical lens, we assume i Lens to be a thin lens having small thickness. All the light rays incident on it converge and actually meet at one point on the principal axis. Answer: The angle of incidence in this case would be 50°, hence the angle of reflection will be 50°. For a concave mirror, the reciprocal of its focal length f is equal to the sum of the reciprocals of image distance v and the object distance u.