When light enters a closed room through a small hole in the door, the image of an outside building appears as inverted on the opposite wall. This is because (a) The hole acts as a convex lens (b) Light takes curvature at the edges of the hole (c) Of rectilinear propagation of light (d) The hole acts as a concave lens

When light enters a closed room through a small hole in the door, the image of an outside building appears as inverted on the opposite wall. This is because (a) The hole acts as a convex lens (b) Light takes curvature at the edges of the hole (c) Of rectilinear propagation of light (d) The hole acts as a concave lens
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A small hole in the window of a closed room forms an inverted image of outside building on the opposite wall of the room. This happens because (a) the rays of light suffer lateral inversion on entering the hole (b) of the rectilinear propagation of light (c) the hole acts as a convex lens (d) the hole acts as a prism

Description : A small hole in the window of a closed room forms an inverted image of outside building on the opposite wall of the room. This happens because (a) the rays of light suffer lateral inversion on entering the ... propagation of light (c) the hole acts as a convex lens (d) the hole acts as a prism

Last Answer : Ans:(b)

Draw the ray diagram in each case to show the position and nature of the image formed when the object is placed: (i) at the centre of curvature of a concave mirror (ii) between the pole P and focus F of a concave mirror (iii) in front of a convex mirror (iv) at 2F of a convex lens (v) in front of a concave lens -Physics

Description : Draw the ray diagram in each case to show the position and nature of the image formed when the object is placed: (i) at the centre of curvature of a concave mirror (ii) between the pole P and focus F of ... front of a convex mirror (iv) at 2F of a convex lens (v) in front of a concave lens -Physics

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: Virtual ... : Virtual, erect and diminished image is formed between O and F on the same side of object.

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`.

A water tank appears shallower when it is viewed from top due to – (1) rectilinear propagation of light (2) reflection (3) total internal reflection (4) refraction

Description : A water tank appears shallower when it is viewed from top due to – (1) rectilinear propagation of light (2) reflection (3) total internal reflection (4) refraction

Last Answer : (4) refraction Explanation: This phenomenon is because of refraction of light. The lines of sight intersect at a higher position than where the actual rays originated. This causes the water to appear shallower than it really is.

A water tank appears shallower when it is viewed from top due to – (1) rectilinear propagation of light (2) reflection (3) total internal reflection (4) refraction

Description : A water tank appears shallower when it is viewed from top due to – (1) rectilinear propagation of light (2) reflection (3) total internal reflection (4) refraction

Last Answer : (4) refraction Explanation: This phenomenon is because of refraction of light. The lines of sight intersect at a higher position than where the actual rays originated. This causes the water to appear ... depth that the water appears to be when viewed from above is known as the apparent depth.

A water tank appears shallower when it is viewed from top due to (1) rectilinear propagation of light (2) reflection (3) total internal reflection (4) refraction

Description : A water tank appears shallower when it is viewed from top due to (1) rectilinear propagation of light (2) reflection (3) total internal reflection (4) refraction

Last Answer : refraction

A concave lens can form a real and inverted image, when : (a) Object is placed at 2f (b) Object is placed beyond 2f (c) Object is placed between f and 2f (d) It can never form a real and

Description : A concave lens can form a real and inverted image, when : (a) Object is placed at 2f (b) Object is placed beyond 2f (c) Object is placed between f and 2f (d) It can never form a real and

Last Answer : (d) It can never form a real and inverted image.

A concave lens always forms an image which is – (1) Real and erect (2) Virtual and erect (3) Real and inverted (4) Virtual and inverted

Description : A concave lens always forms an image which is – (1) Real and erect (2) Virtual and erect (3) Real and inverted (4) Virtual and inverted

Last Answer : (2) Virtual and erect Explanation: Concave lens possesses at least one surface that curves inwards. It is a diverging lens, spreading out those light rays that have been refracted through it. A concave ... is virtual, upright, and smaller than the object, and it cannot be projected onto a screen.

A concave lens always forms an image which is (1) real and erect (2) virtual and erect (3) real and inverted (4) virtual and inverted

Description : A concave lens always forms an image which is (1) real and erect (2) virtual and erect (3) real and inverted (4) virtual and inverted 

Last Answer : virtual and erect

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 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:

In case of convex lens when the image formed is real, inverted and same size as the object then the object should have been at ______ position of lens. a) infinity b)focus c)2F d)between F and 2F

Description : In case of convex lens when the image formed is real, inverted and same size as the object then the object should have been at ______ position of lens. a) infinity b)focus c)2F d)between F and 2F

Last Answer : c)2F

When a person enters a dark room from bright light, he is not able to see clearly for a little while because the (a) eye is unable to adjust itself immediately (b) retina becomes insensitive momentarily (c) iris is unable to dilate the pupil immediately (d) distance between the lens and retina takes time to adjust

Description : When a person enters a dark room from bright light, he is not able to see clearly for a little while because the (a) eye is unable to adjust itself immediately (b) retina becomes insensitive ... is unable to dilate the pupil immediately (d) distance between the lens and retina takes time to adjust

Last Answer : Ans:(c)

An object is placed beyond 2F, in front of a convex lens, image will be formed : (a) between F and 2F (b) at focus (c) at the centre of curvature (d) between focus and Optical centre

Description : An object is placed beyond 2F, in front of a convex lens, image will be formed : (a) between F and 2F (b) at focus (c) at the centre of curvature (d) between focus and Optical centre

Last Answer : (a) between F and 2F

A concave lens always forms – (1) a real image (2) a virtual image (3) an Image type which depends on object characteristics (4) an image type which depends on lens curvature

Description : A concave lens always forms – (1) a real image (2) a virtual image (3) an Image type which depends on object characteristics (4) an image type which depends on lens curvature

Last Answer : (2) a virtual image Explanation: Concave lens always form the virtual and erect image and the image is always diminished. Convex lens forms real image as well as virtual image. It forms both enlarged image and the diminished image.

A concave lens always forms (1) a real image (2) a virtual image (3) an image type which depends on object characteristics (4) an image type which depends on lens curvature

Description : A concave lens always forms (1) a real image (2) a virtual image (3) an image type which depends on object characteristics (4) an image type which depends on lens curvature

Last Answer : a virtual image

There are 100 light bulbs lined up in a row in a long room. Each bulb has its own switch and is currently switched off. The room has an entry door and an exit door. There are 100 people lined up outside the entry door. Each bulb is numbered consecutively from 1 to 100. So is each person. Person No. 1 enters the room, switches on every bulb, and exits. Person No. 2 enters and flips the switch on every second bulb (turning off bulbs 2, 4, 6, ...). Person No. 3 enters and flips the switch on every third bulb (changing the state on bulbs 3, 6, 9, ...). This continues until all 100 people have passed through the room. What is the final state of bulb No. 64? And how many of the light bulbs are illuminated after the 100th person has passed through the room? -Riddles

Description : There are 100 light bulbs lined up in a row in a long room. Each bulb has its own switch and is currently switched off. The room has an entry door and an exit door. There are 100 people ... And how many of the light bulbs are illuminated after the 100th person has passed through the room? -Riddles

Last Answer : First think who will operate each bulb, obviously person #2 will do all the even numbers, and say person #10 will operate all the bulbs that end in a zero. So who would operate for example bulb 48: Persons numbered: 1 & 48 ... 100 (1, 4, 9, 16, 25, 36, 49, 64, 81 & 100) hence 10 bulbs remain on.

A camera uses a ----- to form an image. A. convex lens (Answer) B. concave lens C. condenser lens D. none of these

Description : A camera uses a ----- to form an image. A. convex lens (Answer) B. concave lens C. condenser lens D. none of these

Last Answer : A. convex lens (Answer)

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.

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 camera uses a ______ to form an image on a piece of film at the back. (1) convex lens (2) concave lens (3) diverging lens (4) none of these

Description : A camera uses a ______ to form an image on a piece of film at the back. (1) convex lens (2) concave lens (3) diverging lens (4) none of these

Last Answer : (1) convex lens Explanation: A camera consists of three main parts. • The body which is light tight and contains all the mechanical parts. • The lens which is a convex lens. • The film or a charged couple device in the case of a digital camera.

By which one of the following can a real image be produced? Can it be produced by a: w) concave mirror x) plane mirror y) diverging lens z) convex mirror

Description : By which one of the following can a real image be produced? Can it be produced by a: w) concave mirror x) plane mirror y) diverging lens z) convex mirror

Last Answer : ANSWER: W -- CONCAVE MIRROR

A rear-view mirror for driving is – (1) plain (2) concave (3) convex (4) inverted

Description : A rear-view mirror for driving is – (1) plain (2) concave (3) convex (4) inverted

Last Answer : (3) convex Explanation: The kind of mirror used in the rear-view mirror must be convex mirrors, because it creates smaller, yet still upright images. Concave mirrors would create an inverted image and ... make everything smaller so this allows the driver to see a greater range of things behind him.

A rear-view mirror for driving is (1) plain (2) concave (3) convex (4) inverted

Description : A rear-view mirror for driving is (1) plain (2) concave (3) convex (4) inverted

Last Answer : convex

The figure shows the front view of a convex lens, which originally had only one edge. Five holes of different shapes, namely triangle, square, pentagon, hexagon and circle, were drilled through it at points P, Q, R, S and T in such a way that the holes were parallel to each other, perpendicular to the edge and all the holes were still within the lens edge. What is the total number of edges in the lens after the holes were drilled?

Description : The figure shows the front view of a convex lens, which originally had only one edge. Five holes of different shapes, namely triangle, square, pentagon, hexagon and circle, were drilled through it at points P ... . What is the total number of edges in the lens after the holes were drilled? 

Last Answer : 57

A dentist concave mirror has a radius of curvature of `30 cm`. How far must it be placed from a small cavity in order to get a virtual image magnified

Description : A dentist concave mirror has a radius of curvature of `30 cm`. How far must it be placed from a small cavity in order to get a virtual image magnified

Last Answer : A dentist concave mirror has a radius of curvature of `30 cm`. How far must it be placed from a ... order to get a virtual image magnified `5` times ?

Which of the following is used to split white light into different colours? (1) Glass slab (2) Convex lens (3) Concave lens (4) Prism

Description : Which of the following is used to split white light into different colours? (1) Glass slab (2) Convex lens (3) Concave lens (4) Prism

Last Answer : (4) Prism Explanation: In optics, a prism is a transparent optical element with flat, polished surfaces that refract light. At least two of the flat surfaces must have an angle between them. The ... a triangular base and rectangular sides, and in colloquial use "prism" usually refers to this type.

When beam of parallel rays of light falls on _______ then all the rays of light converge . a) convex lens b)concave lens c)plain mirror d)plano concave lens

Description : When beam of parallel rays of light falls on _______ then all the rays of light converge . a) convex lens b)concave lens c)plain mirror d)plano concave lens

Last Answer : a) convex lens

Which of the following is used to split white light into different colours ? (1) Glass slab (2) Convex lens (3) Concave lens (4) Prism

Description : Which of the following is used to split white light into different colours ? (1) Glass slab (2) Convex lens (3) Concave lens (4) Prism

Last Answer : Prism

When a person enters a dark room from bright light he is not able to see clearly for a little while because the? A. Eye is unable to adjust itself immediately B. Retina becomes insensitive momentarily C. Iris is unable to dilate the pupil immediately (Answer) D. Distance between the lens and retina take time to adjust

Description : When a person enters a dark room from bright light he is not able to see clearly for a little while because the? A. Eye is unable to adjust itself immediately B. Retina becomes insensitive ... to dilate the pupil immediately (Answer) D. Distance between the lens and retina take time to adjust

Last Answer : C. Iris is unable to dilate the pupil immediately (Answer)

When a person enters a dark room from bright light he is not able to see clearly for little while because ______ A. Eye is unable to adjust itself immediately B. Retina becomes insensitive momentarily C. Iris is unable to dilate the pupil immediately D. Distance between the lens and retina take time to adjust

Description : When a person enters a dark room from bright light he is not able to see clearly for little while because ______ A. Eye is unable to adjust itself immediately B. Retina becomes insensitive ... is unable to dilate the pupil immediately D. Distance between the lens and retina take time to adjust

Last Answer : ANSWER: C

The two surfaces of a double concave lens are of curvature 10 cm and 40 cm. Find the focal length of the lens in water. The refractive index of water

Description : The two surfaces of a double concave lens are of curvature 10 cm and 40 cm. Find the focal length of the lens in water. The refractive index of water

Last Answer : The two surfaces of a double concave lens are of curvature 10 cm and 40 cm. Find the focal length of ... and that of the lens of the material is 3/2.

The radii of curvature of each surface of a convex lens is `20 cm` and the refractive index of the material of the lens is `3//2` (i) Calculate its fo

Description : The radii of curvature of each surface of a convex lens is `20 cm` and the refractive index of the material of the lens is `3//2` (i) Calculate its fo

Last Answer : The radii of curvature of each surface of a convex lens is `20 cm` and the refractive index of the ... What happens if the lens is cut along `CD` ?

The focal length of a plano-convex lens is 20 cm in air. Refractive index of glass is 1.5. Calculate (i) the radius of curvature of lens surface and (

Description : The focal length of a plano-convex lens is 20 cm in air. Refractive index of glass is 1.5. Calculate (i) the radius of curvature of lens surface and (

Last Answer : The focal length of a plano-convex lens is 20 cm in air. Refractive index of glass is 1.5. ... length when immersed in liquid of refractive index 1.6

The focal length of a double convex lens is equal to radius of curvature of either surface. The refractive index of its material is

Description : The focal length of a double convex lens is equal to radius of curvature of either surface. The refractive index of its material is

Last Answer : The focal length of a double convex lens is equal to radius of curvature of either surface. The refractive index of its material is

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.

In Newton’s rings experiment, if we reduce the radius of curvature of Plano Convex lens to zero, what will be effect on Newton’s rings? (a)They will become more bright (b)They will become more dark ( c)They will disappear (d) They will be more dense

Description : In Newton’s rings experiment, if we reduce the radius of curvature of Plano Convex lens to zero, what will be effect on Newton’s rings? (a)They will become more bright (b)They will become more dark ( c)They will disappear (d) They will be more dense

Last Answer : ( c)They will disappear

Newton’s rings experiment is performed and radius (or diameter) is calculated. Now Plano-convex lens is replaced with another Plano-convex lens of greater Radius of curvature. What will be effect on radius (or diameter)? (a) Radius (or diameter) will remain constant but there will be more brightness (b) Radius (or diameter) will increase (c) Radius (or diameter) will decrease (d) There will be no effect

Description : Newton's rings experiment is performed and radius (or diameter) is calculated. Now Plano-convex lens is replaced with another Plano-convex lens of greater Radius of curvature. What will be effect on radius ( ... ) will increase (c) Radius (or diameter) will decrease (d) There will be no effect

Last Answer : (b) Radius (or diameter) will increase

In Newton’s rings experiment, if we reduce the radius of curvature of Plano convex lens to zero, what will be effect on Newton’s rings? A. They will become brighter B. They will become darker C. They will disappear D. They will be more dense

Description : In Newton’s rings experiment, if we reduce the radius of curvature of Plano convex lens to zero, what will be effect on Newton’s rings? A. They will become brighter B. They will become darker C. They will disappear D. They will be more dense

Last Answer : C. They will disappear

There is a lamp inside a photography darkroom. When the darkroom door is closed, it is impossible to tell from outside the room whether or not the lamp is on. There are two switches outside the door of the darkroom. One or both of the switches may control the lamp. It also could be that neither of the switches control the lamp. All you know is that the light bulb is currently off and that the lamp and bulb are in working condition. The darkroom door is closed and once you open the door you cannot touch either of the switches. If you can only open the dark-room door one time, how can you tell which switches, if any, control the lamp? -Riddles

Description : There is a lamp inside a photography darkroom. When the darkroom door is closed, it is impossible to tell from outside the room whether or not the lamp is on. There are two switches outside the door of ... dark-room door one time, how can you tell which switches, if any, control the lamp? -Riddles

Last Answer : Turn the first switch on and leave it on for ten minutes. After ten minutes, turn that switch off and turn the second switch on. Open the darkroom door, and lightly (in case it is hot) touch the ... one controls the lamp. If the lamp is off, and the bulb is cool, neither switch controls the lamp.

Why is concave mirror used and not convex mirror? (a) because concave mirror can give real image. (b) because convex mirror can give real image. (c) because concave mirror cannot give real image. (d) because convex mirror cannot give virtual image.

Description : Why is concave mirror used and not convex mirror? (a) because concave mirror can give real image. (b) because convex mirror can give real image. (c) because concave mirror cannot give real image. (d) because convex mirror cannot give virtual image.

Last Answer : (a) because concave mirror can give real image.

Formation of shadows can be explained by - (1) rectilinear propagation of light (2) reflection (3) refraction (4) total internal reflection

Description : Formation of shadows can be explained by - (1) rectilinear propagation of light (2) reflection (3) refraction (4) total internal reflection

Last Answer : (1) rectilinear propagation of light Explanation: In this position, the head light will be at the principal focus so that the rays of light falling on the concave mirror will be rendered parallel

Formation of shadows can be explained by - (1) rectilinear propagation of light (2) reflection (3) refraction (4) total internal reflection

Description : Formation of shadows can be explained by - (1) rectilinear propagation of light (2) reflection (3) refraction (4) total internal reflection

Last Answer : (1) rectilinear propagation of light Explanation: In this position, the head light will be at the principal focus so that the rays of light falling on the concave mirror will be rendered parallel.

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.

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)

Convex mirror always forms, an image : (a) Virtual, erect and enlarged enlarged (c) Virtual, erect and diminished (b) Virtual, inverted and (d) Real, erect and diminished

Description : Convex mirror always forms, an image : (a) Virtual, erect and enlarged enlarged (c) Virtual, erect and diminished (b) Virtual, inverted and (d) Real, erect and diminished

Last Answer : (c) Virtual, erect and diminished

In Fresnel diffraction A. source of light is kept at infinite distance from the aperture B. source of light is kept at finite distance from the aperture C. Convex lens used D. aperture width is selected so that it can acts as a point source

Description : In Fresnel diffraction A. source of light is kept at infinite distance from the aperture B. source of light is kept at finite distance from the aperture C. Convex lens used D. aperture width is selected so that it can acts as a point source

Last Answer : B. source of light is kept at finite distance from the aperture

A concave mirror forms real, inverted and enlarged image at infinity. Where is the object kept a) at F b)at C c)between F and C d)beyond C

Description : A concave mirror forms real, inverted and enlarged image at infinity. Where is the object kept a) at F b)at C c)between F and C d)beyond C

Last Answer : a) at F

Which of the following can be used as a burning glass? (a) Plane mirror (b) Convex mirror (c) Concave lens (d) Concave mirror

Description : Which of the following can be used as a burning glass? (a) Plane mirror (b) Convex mirror (c) Concave lens (d) Concave mirror

Last Answer : Ans:(d)

The lens used in a simple microscope is------? A. Concave B. Convex (Answer) C. Cylindrical D. None

Description : The lens used in a simple microscope is------? A. Concave B. Convex (Answer) C. Cylindrical D. None

Last Answer : B. Convex (Answer)