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

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
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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

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

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.

14. An object 2 cm in size is placed 30 cm in front of a concave mirror of focal length 15 cm. At what distance from the mirror should a screen be placed in order to obtain a sharp image? What will be the nature and the size of the -Chemistry-10

Description : 14. An object 2 cm in size is placed 30 cm in front of a concave mirror of focal length 15 cm. At what distance from the mirror should a screen be placed in order to obtain a sharp image? What will be the nature and the size of the -Chemistry-10

Last Answer : Answer. hope this helps you

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.

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

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

12. Draw ray diagrams to represent the nature, position and relative size of the image formed by a convex lens for the object placed: -Chemistry-10

Description : 12. Draw ray diagrams to represent the nature, position and relative size of the image formed by a convex lens for the object placed: -Chemistry-10

Last Answer : Answer. hope this helps you

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 the image formed if the object is 2 cm high? With the help of a ray diagram show the formation of the image by the lens in this case. -Physics

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:

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.

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

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

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.

3. Draw the ray diagram in each case to show the position and nature of the image formed when the object is placed: -Chemistry-10

Description : 3. Draw the ray diagram in each case to show the position and nature of the image formed when the object is placed: -Chemistry-10

Last Answer : Answer. Nature of image: Real, inverted and same size image is formed at the centre of curvature. Nature of image: Virtual, enlarged and erect image is formed behind the mirror. Nature of image: ... image: Virtual, erect and diminished image is formed between O and F on the same side of object.

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.

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 convex lens and size of the image formed on the screen? Draw a ray diagram to show the formation of the image in this position of the object with respect to the lens. -Physics

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.

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

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.

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

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.

Find the position of an object which when placed in front of a concave mirror of focal length 20 cm, produces a virtual image which is twice the size

Description : Find the position of an object which when placed in front of a concave mirror of focal length 20 cm, produces a virtual image which is twice the size

Last Answer : Find the position of an object which when placed in front of a concave mirror of focal length 20 cm ... image which is twice the size of the object.

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

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

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 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

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

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.

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.

Where should an object be placed from a converging lens of focal length 20 cm, so as to obtain a real image of magnification 2?

Description : Where should an object be placed from a converging lens of focal length 20 cm, so as to obtain a real image of magnification 2?

Last Answer : Where should an object be placed from a converging lens of focal length 20 cm, so as to obtain a real image of magnification 2?

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 image on the screen. (a) In which direction does he move the lens to focus the flame on the screen? (b) What happens to the size of the image of the flame formed on the screen? (c) What difference is seen in the intensity (brightness) of the image of the flame on the screen? (d) What is seen on the screen when the flame is very close (at about 5 cm) to the 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.

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

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

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.

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.

A concave mirror forms a real image four times as tall as the object placed 10 cm infront of mirror. Find the position of the image and the radius of

Description : A concave mirror forms a real image four times as tall as the object placed 10 cm infront of mirror. Find the position of the image and the radius of

Last Answer : A concave mirror forms a real image four times as tall as the object placed 10 cm infront of ... image and the radius of curvature of the mirror.

An object is placed at `0.06` m from a convex lens of focal length `0.1`m. Calculate the position of the image?

Description : An object is placed at `0.06` m from a convex lens of focal length `0.1`m. Calculate the position of the image?

Last Answer : An object is placed at `0.06` m from a convex lens of focal length `0.1`m. Calculate the position of the image?

2. A convex lens forms a real and inverted image of a needle at a distance of 50 cm from it. Where is the needle placed in front of the convex lens if the image is equal to the size of the object? -Physics-10

Description : 2. A convex lens forms a real and inverted image of a needle at a distance of 50 cm from it. Where is the needle placed in front of the convex lens if the image is equal to the size of the object? -Physics-10

Last Answer : The position of the image should be at 2F since the image is the real and same size. It is given that the image of the needle is formed at a distance of 50 cm from the convex lens. Therefore, the needle is ... (u) = - 50 cm Image distance, (v) = 50 cm Focal length = f According to the lens formula,

A sphere of 1 cm radius is placed at the distance of 50 cm from the convex lens of 10 cn focal length. What would be the height of the image of sphere ?

Description : A sphere of 1 cm radius is placed at the distance of 50 cm from the convex lens of 10 cn focal length. What would be the height of the image of sphere ?

Last Answer : 0.5cm

11. Explain with the help of a diagram, why a pencil partly immersed in water appears to be bent at the water surface. [Delhi] -Chemistry-10

Description : 11. Explain with the help of a diagram, why a pencil partly immersed in water appears to be bent at the water surface. [Delhi] -Chemistry-10

Last Answer : Answer. Light from different points on the pencil, immersed in water refracts and appears to come from a point above the original position.

6. “The refractive index of diamond is 2.42”. What is the meaning of this statement in relation to speed of light? [Delhi] -Chemistry-10

Description : 6. “The refractive index of diamond is 2.42”. What is the meaning of this statement in relation to speed of light? [Delhi] -Chemistry-10

Last Answer : Answer. hope this helps you

4. If a light ray IM is incident on the surface AB as shown, identify the correct emergent ray. [Delhi (C)] -Chemistry-10

Description : 4. If a light ray IM is incident on the surface AB as shown, identify the correct emergent ray. [Delhi (C)] -Chemistry-10

Last Answer : Answer. Ray NQ, as it has to be parallel to ray OS.

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

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

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

Description : 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 

Last Answer : (C) 30 cm 

13. A ray of light, incident obliquely on a face of a rectangular glass slab placed in air, emerges from the opposite face parallel to the incident ray. State two factors on which the lateral displacement of the emergent ray depends. [Foreign] -Chemistry-10

Description : 13. A ray of light, incident obliquely on a face of a rectangular glass slab placed in air, emerges from the opposite face parallel to the incident ray. State two factors on which the lateral displacement of the emergent ray depends. [Foreign] -Chemistry-10

Last Answer : Lateral displacement depends on the: angle of incidence, thickness of slab, and refractive index of the material. (any two)

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

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

Last Answer : A convex lens of focal length 30 cm is placed between a screen and a square plate of area ... Calculate the distance between the plate and the screen.

A concave mirror produces a real, inverted image of the same size of the object. Then, the object is at a distance (a) Less than f from the mirror (b) Equal to f from the mirror (c) Equal to 2f from the mirror (d) Larger than 2F from the mirror where f is the focal length of the mirror

Description : A concave mirror produces a real, inverted image of the same size of the object. Then, the object is at a distance (a) Less than f from the mirror (b) Equal to f from the mirror (c) Equal to 2f from the mirror (d) Larger than 2F from the mirror where f is the focal length of the mirror

Last Answer : Ans:(c)

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

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 ?

Where should an object be placed from a converging lens of focal length 10 c, so as to obtain a virtual image of magnification 2 ?

Description : Where should an object be placed from a converging lens of focal length 10 c, so as to obtain a virtual image of magnification 2 ?

Last Answer : Where should an object be placed from a converging lens of focal length 10 c, so as to obtain a virtual image of magnification 2 ?

Ray coming from an object situated at infinity, fall on a convex lens and an image is formed at a distance of 16 cm from the lens. When a concave lens

Description : Ray coming from an object situated at infinity, fall on a convex lens and an image is formed at a distance of 16 cm from the lens. When a concave lens

Last Answer : Ray coming from an object situated at infinity, fall on a convex lens and an image is formed ... . Calculate the focal length of the concave lens.

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?

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

The focal length of a concave mirror is 10 cm and the distance from the mirror to the object is 5 cm . If so, what will be the reflection ?

Description : The focal length of a concave mirror is 10 cm and the distance from the mirror to the object is 5 cm . If so, what will be the reflection ?

Last Answer : The reflection will be unreal and straightforward.

The focal length of a concave-convex lens of radii of curvature 5 cm and 10 cm is 20 cm. what will be its focal length in water ? Given `.^(a)mu_(w) =

Description : The focal length of a concave-convex lens of radii of curvature 5 cm and 10 cm is 20 cm. what will be its focal length in water ? Given `.^(a)mu_(w) =

Last Answer : The focal length of a concave-convex lens of radii of curvature 5 cm and 10 cm is 20 cm. what will be its ... water ? Given `.^(a)mu_(w) = 4//3`.

An object is placed at a distance of 12 cm in front of a concave mirror of radius of curvature 30 cm. List four characteristics of the image formed by the mirror. -Science

Description : An object is placed at a distance of 12 cm in front of a concave mirror of radius of curvature 30 cm. List four characteristics of the image formed by the mirror. -Science

Last Answer : Here, radius of curvature of concave mirror, R = 30 cm. Therefore, focal length of the mirror, f = R/2 = 30/2 = 15 cm Also, object distance, u = 12 cm Hence, knowing the focal length of mirror and ... (i) Erect (ii) Larger in size than that of the object (iii) Virtual and (iv) Behind the mirror.

An object of height 4 cm is kept at a distance of 80 cm from the pole af a diverging mirror. If the focal length of the mirror is 10 cm. the height of the image formed is (a) + 3.0 cm (b) + 2.5 cm (c) + 1.0 cm (d) + 0.75 cm

Description : An object of height 4 cm is kept at a distance of 80 cm from the pole af a diverging mirror. If the focal length of the mirror is 10 cm. the height of the image formed is (a) + 3.0 cm (b) + 2.5 cm (c) + 1.0 cm (d) + 0.75 cm

Last Answer : (c) + 1.0 cm

A compound lens has been formed by joinined a convex and a concave lens, each of focal length 30 cm. what is the focal length of the combination? What

Description : A compound lens has been formed by joinined a convex and a concave lens, each of focal length 30 cm. what is the focal length of the combination? What

Last Answer : A compound lens has been formed by joinined a convex and a concave lens, each of focal length 30 ... of the combination? What will be the power ?

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