Hence, if u and v are measured we can calculate f Two pins are required, one to act as an object and the other as a search pin. Lens Formula: The relation between object distance u , image distance v and focal length f of lens is given by This expression is valid for all the various positions of the object with a spherical lens including the virtual image formed by concave lens or a convex lens. Question 7: What is radius of curvature? Answer: c Explanation: As the reflected rays are converging at focus. Answer: Yes, it is true. The object pin was placed between F and C. Answer: Real, inverted and diminished i.
The mirror must be a parabolic b concave c convex d all of these Question 6: A student selected the sun as a distant object to find the focal length of a concave 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. On which structure we get the image? 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. For best results, attention should be given to the tilt of the plane mirror so that the tip of the image and the tip of the object pin appear to touch Experiments to measure the focal length of a converging lens at the same level as the centre of the lens. The figure drawn by her is given below The point at which she had placed the screen during her experiment was a at A b at B c at C d at D Question 6: If the upper half portion of the lens is covered with black paper, the effect on image is a upper half of the image will be absent b the brightness of the image will be reduced c size of the image depends on covered area of lens d there will be no effect Question 7: Which of the following can be used to find the focal length of a convex lens? Answer: Outer surface is silvered and regular reflection takes place from the inner surface of the mirror. The eye should be fixed on the pin, and the image will be seen to move backwards and forwards as the pin is moved to and fro. Answer: c Explanation: Convex mirror does not form real focus.
What is the angle of incidence and angle of reflection of this ray? Question 9: You are standing facing a mirror and your image appears to be as follows: Head — appears to be very big Body — appears to be of same size Legs — appear to be very small. 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. Distant object can be considered to be at infinity. Question 37: The focal length of the concave mirror in the experimental set-up shown below, equals: a 10. Question 30: The mirror used in car head light is: a concave b convex c plane d concavo-convex. Hence, concave lens images are always virtual images.
The focal length of the concave mirror is a 11. Question 2: With the help of a diagram, differentiate between a converging and diverging lens. It is because a white paper is not available in the lab. A convex mirror always forms virtual image of a real object and hence the value of v i. Find the index-correction between the mirror M and the image needle I.
Answer: a Explanation: Concave mirror acts as reflectors to focus light. We would like to suggest that you combine the reading of this page with the use of our or our. Example Problem 1 A 4. Question 4: What do you mean by infinity? Question 5: What is the difference between a real and virtual image? A focal point is located 20. An object is placed 12 cm from the mirror.
Determine the image distance and the image size. What should be the correct position of screen as suggested by the students and why? Answer: The ratio of the sine of the incident angle to the sine of refracted angle is a constant and is equal to the refractive index of second medium with respect to first medium i. In the case of the image height, a positive value indicates an upright image. When the object is kept between pole and its focus, a virtual image is obtained, whereas a real image is obtained for all other positions of the object. A mean value for the focal length f may then be calculated.
In which case will the student get more accurate value of focal length? Experiment: Find the focal length of a convex mirror using a convex lens. Question 10: State the laws of reflection of light. The virtual image cannot be taken on the screen. The definition Kluckhorn gives relies heavily on common sense. Question 5: What type of mirror is used in a torch? Question 3: The image formed by a mirror is always virtual. Steinbeck draws on this form of genre to present the idea that we are all a part of what happens to others, based upon our nature. The results of this calculation agree with.
Product Description This is virtual lab practical related with optical physics. Question 38: A convex mirror has focal length of 15 cm. In addition, it's the values a person was taught. Questions based on Observational Skills Question 24: A concave mirror gives virtual, erect and enlarged image of the object when placed a at infinity b between F and C c between F and P d at F Answer: c Explanation: When object is placed between F and P, then the reflected rays do not really meet. Question 15: When does concave mirror form a virtual image? 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.
In which case will the student is closer to accurate value of focal length? Answer: The distance between the pole and the focus of a mirror is called focal length of the concave mirror. Answer: b Explanation: On retina real and inverted image is formed. Her red hair lay in wet, matted strings over her shoulders and breasts. 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? State one use of a convex lens. Before reporting your focal length values in the chart below, remember to reproportion them to the original size of the optical bench's measurements.