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

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 

by

1 Answer

Answer :

(D) All the above 

by

Related questions

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

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

Two thin lenses of power `+ 3 D and - 1 D` are held contact with each other. Focal length of the combination is :

Description : Two thin lenses of power `+ 3 D and - 1 D` are held contact with each other. Focal length of the combination is :

Last Answer : Two thin lenses of power `+ 3 D and - 1 D` are held contact with each other. Focal length of the combination is :

Diopter is the power of a lens having a focal length of (A) 25 cm (B) 50 cm (C) 75 cm (D) 100 cm

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

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 

Pick up the correct specification of Ramsden eyepiece from the following: (A) It consists of two equal piano convex lenses (B) The curved surfaces of Plano-convex lenses face each other (C) The distance between the diaphragm and the front lens of the eyepiece is kept equal to 1/4 th of the focal length of a lens so that rays from a point on the diaphragm enter the eye as a parallel beam (D) All the above

Description : Pick up the correct specification of Ramsden eyepiece from the following:  (A) It consists of two equal piano convex lenses  (B) The curved surfaces of Plano-convex lenses face each other  (C) ... from a point on the diaphragm enter the eye as a  parallel beam  (D) All the above 

Last Answer : (D) All the above 

Pick up the correct statement from the following: (A) Spherical aberration may be reduced by diminishing the aperture (B) Spherical aberration may be minimised by replacing the single lens by a combination of the lenses (C) In telescope objectives, a combination of convex lens and concave lens is used (D) All the above

Description : Pick up the correct statement from the following: (A) Spherical aberration may be reduced by diminishing the aperture (B) Spherical aberration may be minimised by replacing the single lens by a ... telescope objectives, a combination of convex lens and concave lens is used (D) All the above

Last Answer : (D) All the above

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?

Description : 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?

Last Answer : 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?

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

Description : 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

Last Answer : A concave lens is kept in contact with a convex lens of focal length `20 cm`. The combination ... length `100 cm`. Calculate power of concave lens.

In the following diagram are shown the position of an object O, image I and two lenses. The focal length of one lens is also given. Determine the foca

Description : In the following diagram are shown the position of an object O, image I and two lenses. The focal length of one lens is also given. Determine the foca

Last Answer : In the following diagram are shown the position of an object O, image I and two lenses. The ... given. Determine the focal length of the other lens.

Pick up the correct statement from the following: (A) A refracting telescope consists optically of two lenses (B) The principal axes of both the lenses coincide the optical axis of the telescope(C) The lens nearer the object to be viewed is convex and is called objective (D) All the above

Description : Pick up the correct statement from the following: (A) A refracting telescope consists optically of two lenses (B) The principal axes of both the lenses coincide the optical axis of the telescope (C) The lens nearer the object to be viewed is convex and is called objective (D) All the above

Last Answer : (D) All the above

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 ?

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

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.

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

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 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 lens or combination of lenses in which the following defect is completely eliminated is called aplanatic (A) Spherical aberration (B) Chromatic aberration (C) Coma (D) Astigmatism

Description : A lens or combination of lenses in which the following defect is completely eliminated is called aplanatic (A) Spherical aberration (B) Chromatic aberration (C) Coma (D) Astigmatism

Last Answer : (A) Spherical aberration

Dioptere is the unit of – (1) power of a lens (2) focal length of a lens (3) light intensity (4) sound intensity

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 : (1) power of a lens

Dioptere is the unit of (1) power of a lens (2) focal length of a lens (3) light intensity (4) sound intensity

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

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 and neutralise the dispersion produced by the convex lens at the emergence from the concave (D) All the above

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

Last Answer : (D) All the above

Anyone out there using Bausch & Lomb Multi-Focal contact lenses?

Description : Anyone out there using Bausch & Lomb Multi-Focal contact lenses?

Last Answer : I don’t use the multi-focal, I don’t think. I use the ones that are two different strengths and allow you to see close up and far away. They simulate bi-focals. If these are multi-focals I like them very much and have worn them for about three years.

Pick up the incorrect statement from the following: The torsional resistance of a shaft is directly proportional to (A) Modulus of rigidity (B) Angle of twist (C) Reciprocal of the length of the shaft (D) Moment of inertia of the shaft section

Description : Pick up the incorrect statement from the following: The torsional resistance of a shaft is directly  proportional to  (A) Modulus of rigidity  (B) Angle of twist  (C) Reciprocal of the length of the shaft  (D) Moment of inertia of the shaft section 

Last Answer : (D) Moment of inertia of the shaft section 

An object located four focal lengths in front of a thin, converging lens is moved to within two focal lengths of the lens. As a result, does the size of the image produced by the lens increase, decrease or remain the same?

Description : An object located four focal lengths in front of a thin, converging lens is moved to within two focal lengths of the lens. As a result, does the size of the image produced by the lens increase, decrease or remain the same?

Last Answer : ANSWER: INCREASE

Large astronomical telescopes always use as objective (a) Lens (b) Mirror (c) Combination of lenses (d) None of the above

Description : Large astronomical telescopes always use as objective (a) Lens (b) Mirror (c) Combination of lenses (d) None of the above

Last Answer : Ans:(a)

If f1 and f2 are the distances from the optical centre of a convex lens of focal length to conjugate two points P1 and P2 respectively, the following relationship holds good (A) f = f1 + f2 (B) f = ½ (f1 + f2) (C) 1/f = 1/f1 + 1/f2 (D) None of these

Description : If f1 and f2 are the distances from the optical centre of a convex lens of focal length to conjugate two points P1 and P2 respectively, the following relationship holds good (A) f = f1 + f2 (B) f = ½ (f1 + f2) (C) 1/f = 1/f1 + 1/f2 (D) None of these

Last Answer : (C) 1/f = 1/f1 + 1/f2

In a telescope the object glass of focal length 14 cm, is located at 20 cm from the diaphragm. The focussing lens is midway between them when a staff 16.50 m away is focussed. The focal length of the focussing lens, is (A) 5.24 cm (B) 6.24 cm (C) 7.24 cm (D) 8.24 cm

Description : In a telescope the object glass of focal length 14 cm, is located at 20 cm from the diaphragm. The focussing lens is midway between them when a staff 16.50 m away is focussed. The focal length of the focussing lens, is (A) 5.24 cm (B) 6.24 cm (C) 7.24 cm (D) 8.24 cm

Last Answer : (C) 7.24 cm

In the following ray diagram are given the position of an object O, image I and two lenses `L_(1)` and `L_(2)`. The focal length of `L_(1)` is also gi

Description : In the following ray diagram are given the position of an object O, image I and two lenses `L_(1)` and `L_(2)`. The focal length of `L_(1)` is also gi

Last Answer : In the following ray diagram are given the position of an object O, image I and two lenses `L_(1)` ... also given. Find the focal length of `L_(2)`.

If the powers of the lenses L 1 and L 2 are in the ratio of 4:1, what would be the ratio of the focal length of L 1 and L 2 ? (a) 4:1 (b) 1:4 (c) 2:1 (d) 1:1

Description : If the powers of the lenses L 1 and L 2 are in the ratio of 4:1, what would be the ratio of the focal length of L 1 and L 2 ? (a) 4:1 (b) 1:4 (c) 2:1 (d) 1:1

Last Answer : (a) 4:1

The focal length of a convex lens is 50 cm. what is its power? -Do You Know?

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

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

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)

The focal length of a convex lens is 50 cm. what is its power?

Description : The focal length of a convex lens is 50 cm. what is its power?

Last Answer : +2 D

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. The Karakoram Highway connects which pair of countries? 5. Who was the Governor General tomerge Sindh in British India?

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

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

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.

16. Find the focal length of a lens of power -2.0 D. What type of lens is this? -Physics-10

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.

3. Find the power of a concave lens of focal length 2 m. -Physics-10

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

The focal length of the lens in a photographic camera is 5 cm. What is the power of the lens? -Do You Know?

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

What is the power of a lens if the focal length of a lens is + 0.1 m ?

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]

What is the power of a convex lens with a focal length of 20 cm ?

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

The focal length of the lens in a photographic camera is 5 cm. What is the power of the lens?

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

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

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)

Suppose the power of a prescription lens is 4 diopters. What is the focal length of the lens?

Description : Suppose the power of a prescription lens is 4 diopters. What is the focal length of the lens?

Last Answer : ANSWER: = 25 CENTIMETERS

Pick out the wrong statement. (A) Reciprocal of the resistance to heat flow is called thermal conductance (B) Unit of thermal conductance is W/°K (C) Thermal conductance of a wall of thickness 'L', thermal conductivity 'k' and heat flow area 'A' is kL/A (D) None of these

Description : Pick out the wrong statement. (A) Reciprocal of the resistance to heat flow is called thermal conductance (B) Unit of thermal conductance is W/°K (C) Thermal conductance of a wall of thickness 'L', thermal conductivity 'k' and heat flow area 'A' is kL/A (D) None of these

Last Answer : (C) Thermal conductance of a wall of thickness 'L', thermal conductivity 'k' and heat flow area 'A' is kL/A

Diopter is the unit of..

Description : Diopter is the unit of..

Last Answer : Power Of lens

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

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

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)`.

Description : 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)`.

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 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 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 ?

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.