Two thin lenses of focal lengths 15 cm and 30 cm resepectively are kept in contact with each other. What is the power of the combined system?

Two thin lenses of focal lengths 15 cm and 30 cm resepectively are kept in contact with each other. What is the power of the combined system?
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Two thin lenses of focal lengths 15 cm and 30 cm resepectively are kept in contact with each other. What is the power of the combined system?
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Two thin lenses of power `+ 3 D and - 1 D` are held contact with each other. Focal length of the combination is :

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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

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Two concave lenses of 60 cm focal length are cemented on either side of a convex lens of 15 cm focal length. The focal length of the combination is (A) 10 cm (B) 20 cm (C) 30 cm (D) 40 cm

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A concave lens is kept in contact with a convex lens of focal length `20 cm`. The combination works as a converging lens of focal length `100 cm`. Cal

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Last Answer : Answer. hope this helps you

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ails are available in various lengths ranging from a ) 1.00 to 15 cm b) 1.25 to 15 cm c) 1.5 to 15 cm d) 2.5 to 15 cm

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A convex lens of focal length 30 cm is placed between a screen and a square plate of area `4cm^(2)`. The image of the plate formed on the screen is `1

Description : A convex lens of focal length 30 cm is placed between a screen and a square plate of area `4cm^(2)`. The image of the plate formed on the screen is `1

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The focal length of a convex lens of glass `(mu = 1.5)` in air is 30 cm. Find its focal length when the lens is placed in water `(mu = 4//3)`.

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Last Answer : The focal length of a convex lens of glass `(mu = 1.5)` in air is 30 cm. Find its focal length when the lens is placed in water `(mu = 4//3)`.

The radii of curvature of a double convex lens are 30 cm and 60 cm and its refractive index is 1.5. calculate its focal length.

Description : The radii of curvature of a double convex lens are 30 cm and 60 cm and its refractive index is 1.5. calculate its focal length.

Last Answer : The radii of curvature of a double convex lens are 30 cm and 60 cm and its refractive index is 1.5. calculate its focal length.

A converging lens forms a three times magnified image of an object, which can be take on a screen. If the focal length of the lens is 30 cm, then the distance of the object from the lens is (a) - 55 cm (b) - 50 cm (c) - 45 cm (d) - 40 cm

Description : A converging lens forms a three times magnified image of an object, which can be take on a screen. If the focal length of the lens is 30 cm, then the distance of the object from the lens is (a) - 55 cm (b) - 50 cm (c) - 45 cm (d) - 40 cm

Last Answer : (d) - 40 cm

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 : 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

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.

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

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

15. An object of size 7.0 cm is placed at 27 cm in front of a concave mirror of focal length 18 cm. At what distance from the mirror should a screen be placed so that a sharply focused image can be obtained? Find the size and nature of the image. -Physics-10

Description : 15. An object of size 7.0 cm is placed at 27 cm in front of a concave mirror of focal length 18 cm. At what distance from the mirror should a screen be placed so that a sharply focused image can be obtained? Find the size and nature of the image. -Physics-10

Last Answer : Object distance (u) = – 27 cm Object height (h) = 7 cm Focal length (f) = – 18 cm According to the mirror formula, The negative value of image height indicates that the image formed is inverted.

12. An object is placed at a distance of 10 cm from a convex mirror of focal length 15 cm. Find the position and nature of the image. -Physics-10

Description : 12. An object is placed at a distance of 10 cm from a convex mirror of focal length 15 cm. Find the position and nature of the image. -Physics-10

Last Answer : Focal length of convex mirror (f) = +15 cm Object distance (u) = - 10 cm According to the mirror formula, The image is located at a distance of 6 cm from the mirror on the other ... and a value of less than 1 of magnification indicates that the image formed is virtual and erect and diminished.

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

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.

We wish to obtain an erect image of an object, using a concave mirror of focal length 15 cm. What should be the range of distance of the object from the mirror? -Physics-10

Description : We wish to obtain an erect image of an object, using a concave mirror of focal length 15 cm. What should be the range of distance of the object from the mirror? -Physics-10

Last Answer : Range of the distance of the object = 0 to 15 cm from the pole of the mirror. Nature of the image = virtual, erect, and larger than the object.

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

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.

A concave mirror of focal length 15 cm can form a magnified, erect as well as inverted image of an object placed in front of it." Justify this statement stating the position of the object with respect to the pole of the mirror in both the cases for obtaining the images. -Science

Description : A concave mirror of focal length 15 cm can form a magnified, erect as well as inverted image of an object placed in front of it." Justify this statement stating the position of the object with respect to the pole of the mirror in both the cases for obtaining the images. -Science

Last Answer : For magnified and erect image the object is placed between pole P and focus F. For magnified and inverted image the object is placed either at focus or anywhere between F and C.

At what distance should an object be placed from a convex lens of focal langth `15 cm` to obtain an image three times the size of the object ?

Description : At what distance should an object be placed from a convex lens of focal langth `15 cm` to obtain an image three times the size of the object ?

Last Answer : At what distance should an object be placed from a convex lens of focal langth `15 cm` to obtain an image three times the size of the object ?

A plano-convex lens `(mu = 1.5)` has a curved surface of radiys 15 cm. what is its focal length ?

Description : A plano-convex lens `(mu = 1.5)` has a curved surface of radiys 15 cm. what is its focal length ?

Last Answer : A plano-convex lens `(mu = 1.5)` has a curved surface of radiys 15 cm. what is its focal length ?

Find the size, nature and position of image formed by a concave mirror, when an object of size 1 cm is placed at a distance of 15 cm. Given focal leng

Description : Find the size, nature and position of image formed by a concave mirror, when an object of size 1 cm is placed at a distance of 15 cm. Given focal leng

Last Answer : Find the size, nature and position of image formed by a concave mirror, when an object of size 1 cm ... 15 cm. Given focal length of mirror is 10 cm.

A positive lens with a focal length of 10 cm forms a real image of an object 20 am away from the lens. How far is the real image from the lens? a. 5 cm b. 10 cm c. 15 cm d. 20 cm

Description : A positive lens with a focal length of 10 cm forms a real image of an object 20 am away from the lens. How far is the real image from the lens? a. 5 cm b. 10 cm c. 15 cm d. 20 cm

Last Answer : d. 20 cm

The focal length of mirror is (a) -16 cm (b) 12 cm (c) -15 cm (d) 10 cm

Description : The focal length of mirror is (a) -16 cm (b) 12 cm (c) -15 cm (d) 10 cm

Last Answer : (a) -16 cm

If the focal length of the object glass is 25 cm and the distance from object glass to the trunnion axis is 15 cm, the additive constant (A) 0.1 (B) 0.4 (C) 0.6 (D) 1.33

Description : If the focal length of the object glass is 25 cm and the distance from object glass to the trunnion axis is 15 cm, the additive constant (A) 0.1 (B) 0.4 (C) 0.6 (D) 1.33

Last Answer : (B) 0.4

A positive lens with a focal length of 10 cm forms a real image of an object 20 am away from the lens. How far is the real image from the lens? ∙ a. 5 cm ∙ b. 10 cm ∙ c. 15 cm ∙ d. 20 cm

Description : A positive lens with a focal length of 10 cm forms a real image of an object 20 am away from the lens. How far is the real image from the lens? ∙ a. 5 cm ∙ b. 10 cm ∙ c. 15 cm ∙ d. 20 cm

Last Answer : ∙ d. 20 cm

Fig. 6(b).54. shows a thin lens with centres of curvature `C_(1) and C_(2)`. If `mu = 1.5`, what is its focal length ?

Description : Fig. 6(b).54. shows a thin lens with centres of curvature `C_(1) and C_(2)`. If `mu = 1.5`, what is its focal length ?

Last Answer : Fig. 6(b).54. shows a thin lens with centres of curvature `C_(1) and C_(2)`. If `mu = 1.5`, what is its focal length ?

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?

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

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?

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

Two goods trains having equal lengths, take 30 seconds and 45 seconds respectively to cross a telegraph post. If the length of each train is 360 meters, in what time (in seconds) will they cross each other when traveling in opposite direction? A) 36 B) 12 C) 24 D) 48

Description :  Two goods trains having equal lengths, take 30 seconds and 45 seconds respectively to cross a telegraph post. If the length of each train is 360 meters, in what time (in seconds) will they cross each other when traveling in opposite direction? A) 36 B) 12 C) 24 D) 48

Last Answer : ANSWER:A  Explanation:  Speed of train = distance /time  = 360/30 m/s  = 12 m/s  Speed of train 2 = distance /time  = 360 /45 m/s  = 8 m/s  If 2 trains are moving in opposite ... +360 = 720 m  Time = distance/speed  = (720/20) = 36 Seconds Hence the required answer is 36 seconds

Two trains of equal lengths take 10 seconds and 15 seconds respectively to cross a telegraph post. If the length of each train be 120 metres, in what time (in seconds) will they cross each other travelling in opposite direction? A.12 sec B.18 sec C.14 sec D.25 sec E.None of these

Description : Two trains of equal lengths take 10 seconds and 15 seconds respectively to cross a telegraph post. If the length of each train be 120 metres, in what time (in seconds) will they cross each other travelling in opposite direction? A.12 sec B.18 sec C.14 sec D.25 sec E.None of these

Last Answer : Answer – A (12 sec) Explanation – Speed of the first train = [120 / 10] m/sec = 12 m/sec. Speed of the second train = [120 / 15] m/sec = 8 m/sec. Relative speed = (12 + 8) = m/sec = 20 m/sec. ∴ Required time = (120 + 120) / 20 secc = 12 sec