Description : Dioptere is the unit of (1) power of a lens (2) focal length of a lens (3) light intensity (4) sound intensity
Last Answer : power of a lens
Description : A student focuses the image of a candle flame, placed at about 2 m from a convex lens of focal length 10 cm, on a screen. After that he moves gradually the flame towards the lens and each time focuses its ... d) What is seen on the screen when the flame is very close (at about 5 cm) to the lens?
Last Answer : (a) The student moves the lens away from the screen to focus the image because on moving the candle towards the lens, the image distance increases. (b)The size of the image increases when the object ... on the screen. A virtual image is formed behind the candle on the same side of the screen.
Description : Pick up the correct statement from the following: (A) The power of a lens is the reciprocal of its focal length (B) The unit of power of the lens is Diopter (C) The power of two or more thin lenses in contact is the power of the combination of the lenses (D) All the above
Last Answer : (D) All the above
Description : What is the power of a lens if the focal length of a lens is + 0.1 m ?
Last Answer : If the focal length of a lens is + 0.1 m then the power of that lens will be p = 1 / f = 1 / 0.1 = 10 D [ here p power , f focus distance]
Description : What is the power of a convex lens with a focal length of 20 cm ?
Last Answer : 20cm = 0.2 m We know , power p = 1 / f = 1 / 0.2 = + 5 D
Description : Suppose the power of a prescription lens is 4 diopters. What is the focal length of the lens?
Last Answer : ANSWER: = 25 CENTIMETERS
Description : A convex lens has a focal length of 10 cm. At what distance from the lens should the object be placed so that it forms a real and inverted image 20 cm away from the lens? What would be the size of ... ? With the help of a ray diagram show the formation of the image by the lens in this case. -Physics
Last Answer : This is the Answe:
Description : An object 2 cm high is placed at a distance of 64 cm from a white screen. On placing a convex lens at a distance of 32 cm from the object it is found that a distinct image of the object ... diagram to show the formation of the image in this position of the object with respect to the lens. -Physics
Last Answer : Since, object-screen distance is double of object-lens separation, the object is at a distance of 2f from the lens and the image should be of the same size of the object.
Description : An object 50 cm tall is placed on the principal axis of a convex lens. Its 20 cm tall image is formed on the screen placed at a distance of 10 cm from the lens. Calculate the focal length of the lens. -Physics
Last Answer : The focal length' of convex length is 7.14 cm. Solution: The given quantities are Height of the object h = 50 cm Height of the image formed h' = -20 cm Image distance v = 10 cm The image ... object distance will be So the focal length will be Thus the focal length of the convex lens is 7.14 cm
Description : A concave lens has focal length of 20 cm. At what distance from the lens a 5 cm tall object be placed so that it forms an image at 15 cm from the lens? Also calculate the size of the image formed. -Physics
Last Answer : Answer. I hope it helped you.
Description : + What is the focal length of a lens of ID capacity ?
Last Answer : + 1D is the focal length of a lens of power f = 1 / p = 1/1 = 1 [ Here f is the focal length , p is the power of the lens]
Description : What is the focal length of a +5d capable lens ?
Last Answer : We know that power is P = 1 / f hence the distance distance f = 1 / p = 1/5 = 0.2 m
Last Answer : : The distance between the center of a lens and the main focus is called the focal length of that lens.
Description : An object is placed on the principal axis of a convex lens of focal length 10 cm. If the distance of the object from the lens is 30 cm, what is the distance of the image formed? (1) 20 cm (2) 15 cm (3) 30 cm (4) 10 cm
Last Answer : (2) 15 cm
Description : Which one of the following determines the sharpness of image in a camera? (1) The aperture (2) The exposure time (3) The focal length of the lens (4) Size of the camera
Last Answer : (1) The aperture Explanation: Image quality is a characteristic of an image that measures the perceived image degradation (typically, compared to an ideal or perfect image). Imaging systems may ... assessment is an important problem. Sharpness determines the amount of detail an image can convey.
Description : The measured distance from a lens to the object is 20 cm and from the lens to the image is 5 cm. Calculate the focal length
Last Answer : 1/4
Description : A converging thin lens has a focal length of 27 centimeters. An object is placed 9 centimeters from the lens. Is the image of the object real or virtual?
Last Answer : ANSWER: VIRTUAL
Description : A 50 millimeter focal length camera lens photographs a 4 meter tall tree at a distance of 20 meters. How tall is the image of the tree?
Last Answer : ANSWER: 10 MILLIMETERS
Description : An object is located 1 meter in front of a converging lens having a focal length of 20 centimeters. At what distance behind the lens (whose thickness is negligible) will the image be formed? w) 18 centimeters x) 20 centimeters y) 22 centimeters z) 25 centimeters
Last Answer : ANSWER: Z -- 25 CENTIMETERS
Description : Your Minolta camera has a 50 millimeter lens. The 50 millimeters is the lens' w) diameter x) focal length y) magnification z) aperture
Last Answer : ANSWER: X -- FOCAL LENGTH
Description : A converging thin lens has a focal length of 27 centimeters. An object is placed 9 centimeters from the lens. Where is the image of this object formed?
Last Answer : ANSWER: -13.5 CENTIMETERS or 13.5 CENTIMETERS ON THE OBJECT SIDE OF THE LENS
Description : Which one of the following determines the sharpness of image in a camera ? (1) The aperture (2) The exposure time (3) The focal length of the lens (4) Size of the camera
Last Answer : The aperture
Description : When a person walking in bright Sunlight enters a dark room, he is not able to see clearly for a little while because (1) the eye muscles cannot immediately adjust the focal length of the eye ... is unable to contract the pupil immediately. (4) the iris is unable to dilate the pupil immediately.
Last Answer : the iris is unable to dilate the pupil immediately.
Description : A source of light and a screen are placed 90 cm apart. Where should a convex lens of 20 cm focal length be placed in order to form a real image of the
Last Answer : A source of light and a screen are placed 90 cm apart. Where should a convex lens of 20 cm focal ... form a real image of the source on the screen ?
Description : 17. A doctor has prescribed a corrective lens of power +1.5 D. Find the focal length of the lens. Is the prescribed lens diverging or converging? -Physics-10
Last Answer : Power of lens (P) = 1/f P = 1.5D f = 1/1.5 = 10/15 = 0.66 m A convex lens has a positive focal length. Therefore, it is a convex lens or a converging lens.
Description : 16. Find the focal length of a lens of power -2.0 D. What type of lens is this? -Physics-10
Last Answer : Power of lens (P) = 1/f P = -2D f = -1/2 = -0.5 m A concave lens has a negative focal length. Therefore, it is a concave lens.
Description : 3. Find the power of a concave lens of focal length 2 m. -Physics-10
Last Answer : Focal length of concave lens (f) = 2 m Power of lens (P) = 1/f = 1/ (-2) = -0.5D
Description : The focal length of the lens in a photographic camera is 5 cm. What is the power of the lens? -Do You Know?
Last Answer : P=100/f (in cms) =100/5 1m= 100cm 0.2m= 20cm Hence,the power is 0.2 D The lens is convex as it is positive
Description : The focal length of a convex lens is 50 cm. what is its power? -Do You Know?
Last Answer : convex ( so focal length is positive ) given : f = 50cm or +50×10^-2m so find p =? formula p =1/f p = 1/50×10^-2 p= 100/50 P = 2
Description : Find the focal length and power of a convex lens, which when placed in contact with a concave lens of focal length `25 cm` forms a real image `5` time
Last Answer : Find the focal length and power of a convex lens, which when placed in contact with a concave ... the object placed `20 cm` from the combination.
Description : The power of a convex lens is +2.5. Then its focal length is (a) 20 cm (b) 50 cm (c) 30 cm (d) 40 cm
Last Answer : Ans:(d)
Description : The focal length of the lens in a photographic camera is 5 cm. What is the power of the lens?
Last Answer : + 20 D
Description : The focal length of a convex lens is 50 cm. what is its power?
Last Answer : +2 D
Description : Magnifying power of a simple microscope can be increased by ? A. increasing focal length of the lens B. Decreasing focal length of the lens (Answer) C. Lens of large aperture D. lens of short aperture E. None of these
Last Answer : B. Decreasing focal length of the lens (Answer)
Description : Diopter is the power of a lens having a focal length of (A) 25 cm (B) 50 cm (C) 75 cm (D) 100 cm
Last Answer : (D) 100 cm
Description : The power of a lens (A) Is reciprocal of its focal length (B) Is positive if it is a convex lens (C) Is negative if it is a concave lens (D) Is measured in Diopter
Last Answer : (D) Is measured in Diopter
Description : Flint glass (A) Has slightly the greater refracting power than crown glass (B) Has roughly double refracting power than that of crown (C) And crown glass proportions yield the required focal length ... dispersion produced by the convex lens at the emergence from the concave (D) All the above
Description : 1. The focal length of a convex lens is 50 cm. what is its power? 2. Among the Indian languages, which one is spoken maximum in the world after Hindi? 3. Which formulates fiscal policy? 4. ... Sun (in million kms.)? 20. Upanishads, also known as the Vedantas, are How many are these upanishads?
Last Answer : Answer : 1. +2 D 2. Bengali 3. Finance Ministry 4. China-Pakistan5. Lord Ellenborough 6. Leaf 7. Advocate General 8. Lithium and osmium 9. Chenab 10. Indigo 11. Canada 12. The Mellanesia 13. Leaf 14. Black 15. Atharvaveda 16. President 17. Roentgens 18. Third Plan 19. 149 20. 108
Description : Decibel is the unit of ______. (1) Speed of light (2) Intensity of sound (3) Intensity of heat (4) None of these
Last Answer : (2) Intensity of sound Explanation: Decibel (dB) unit is used for expressing the ratio between two amounts of electric or acoustic power for measuring the relative loudness of sounds.
Description : Decibel is the unit used for – (1) Speed of light (2) Intensity of heat (3) Intensity of sound (4) Radio wave frequency
Last Answer : (3) Intensity of sound Explanation: The decibel (abbreviated dB) is the unit used to measure the intensity of a sound. The decibel scale is a little odd because the human ear is incredibly ... of a physical quantity (usually power or intensity) relative to a specified or implied reference level.
Description : Decibel is the unit used for (1) Speed of light (2) Intensity of heat (3) Intensity of sound (4) Radio wave frequency
Last Answer : Intensity of sound
Description : Can you explain the difference between a prime/fixed focal length lens and one where the focal length can be varied?
Last Answer : With a zoom lens, you can change the focal length to zoom in or out (there's a proper name for it but it escapes me). With a prime lens, it's fixed - no zoom. Because prime lenses are ... a zoom.. You'd just use them differently and get slightly different results. I think Pros only use prime lenses.
Description : 15. An object 2 cm high is placed at a distance of 64 cm from a white screen. On placing a convex lens at a distance of 32 cm from the object it is found that a distinct image of the object is formed on the screen. What is the focal length of the conve -Chemistry-10
Description : 2. An object 50 cm tall is placed on the principal axis of a convex lens. Its 20 cm tall image is formed on the screen placed at a distance of 10 cm from the lens. Calculate the focal length of the lens. [All India] -Chemistry-10
Last Answer : this is the answer for the respected question
Description : 1. A concave lens has focal length of 20 cm. At what distance from the lens a 5 cm tall object be placed so that it forms an image at 15 cm from the lens? Also calculate the size of the image formed. [Delhi] -Chemistry-10
Last Answer : Answer. hope this helps youu
Description : 11. A concave lens of focal length 15 cm forms an image 10 cm from the lens. How far is the object placed from the lens? Draw the ray diagram. -Physics-10
Last Answer : Focal length of concave lens (OF1), f = – 15 cm Image distance, v= – 10 cm According to the lens formula, The negative value of u indicates that the object is placed 30 cm in front of the lens. This is shown in the following ray diagram.
Description : 10. An object 5 cm in length is held 25 cm away from a converging lens of focal length 10 cm. Draw the ray diagram and find the position, size and the nature of the image formed. -Physics-10
Last Answer : Height of the Object, h0 = 5 cm Distance of the object from converging lens, u = -25 cm Focal length of a converging lens, f = 10 cm Using lens formula, Thus, the image is inverted and formed at a distance of 16.7 cm behind the lens and measures 3.3 cm. The ray diagram is shown below.
Description : 4. A spherical mirror and a thin spherical lens have a focal length of -15 cm. The mirror and the lens are likely to be -Physics-10
Last Answer : (a) Both are likely to be concave.
Description : A needle 10 cm long is placed along the axis of a convex lens of focal length 10 cm such that the middle point of the neddle is at a distance of 10 cm
Last Answer : A needle 10 cm long is placed along the axis of a convex lens of focal length 10 cm such that ... lens. Find the length of the image of the neddle.
Description : A concave lens focal length 10 cm is placed on the axis of concave mirror of 10 cm radius at a distance of 5 cm from the mirror. An object is placed s
Last Answer : A concave lens focal length 10 cm is placed on the axis of concave mirror of 10 cm radius ... the object itself. Determine the position of the object.