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Consider the following statement about the concave lens A. Magnified image cannot be obtained. B. Real and inverted image can be obtained. C. Image is always formed either on focus or focal length. D. Focal length is always negative. Which among the above statements is incorrect?

Consider the following statement about the concave lens A. Magnified image cannot be obtained. B. Real and inverted image can be obtained. C. Image is always formed either on focus or focal length. D. Focal length is always negative. Which among the above statements is incorrect? Correct Answer B

Concept:

Spherical Lens

  • The transparent medium bounded by a spherical surface from both sides is called the spherical lens. 
  • There are basically two types of lens, Concave and convex. 

Concave lens

  • The concave lens has both surfaces curved inward 
  • It is a diverging lens that diverges the parallel beam of light.
  • It can also gather light from all directions and project it as a parallel beam.
  • The focal length of the concave lens is negative.
  • Focus is the point, where rays of light parallel to the lens, appear to come from after refraction. 

Image Formation by Concave lens

Position of object Position of image Relative size Nature of the image Ray diagram
At infinity At Focus F1 Point Size Virtual and erect Additional Information

 Convex lens:

  • The lens whose refracting surface is upside is called a convex lens.
  • The convex lens is also called a converging lens.
  • The focal length of a convex lens is positive.

Sign convention

  • Sign convention for a convex lens is as shown. It is also applicable for concave lens in term of sides. 

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Related Questions

Given below are four statements- (p) The second principal focus of a lens is the position of the object, real or virtual whose image is at infinity. (q) The second principal focus of a lens is the position of the image, real or virtual whose object is at infinity. (r) The first principal focus of a lens is the position of the object, real or virtual whose image is at infinity. (s) The first principal focus of a lens is the position of the image, real or virtual whose object is at infinity.  Examine the above statements and find which among then are correct. 
 Which of the following statements is/are true of the human eye lens? Choose the correct answer from the code given below:  (i) It is a convex lens (ii) It is a concave lens (iii) It is a convex lens of variable focal length (iv) It forms a real and inverted image of a distant object at the retina
Consider the following statements   1. The focal length of the eyepiece is larger than the focal length of the objective. 2. The focal length of the eyepiece is smaller than the focal length of the objective. 3. The aperture of the eyepiece lens is larger than the objective lens. Which of the following statements is/are INCORRECT about a compound microscope?
Consider the following statement 1. When the object is placed at infinity of the convex mirror, then the image is formed at the focus. 2. The image formed by a convex mirror is always real, inverted, and smaller in size. 3. When the object is placed at infinity and pole of the convex mirror, then the image is formed at the focus. Which of the following statements is CORRECT?
Which of the following statements are true? (i) The principal focus of a converging lens is real. (ii) The principal focus of a diverging lens is virtual. (iii) The principal focus of a lens is always along the principal axis.
Consider the following statements: A ray parallel to the principal axis incident on a concave mirror after reflection passes through the focus. A ray passing through the center of curvature of a concave mirror after reflection is reflected back along the same path. A ray passing through the center of curvature of a concave mirror after reflection passes through the focus. Which of the following statement is INCORRECT?
Which statement is correct about telescope: a) The focal length of the objective lens is more than the eyepiece. b) The focal length of the eyepiece is more than the objective lens. c) The aperture of the objective lens is more than the eyepiece. d) The aperture of the eyepiece is more than the objective lens.
Which of the following statements are always true? (i) When the object is placed nearer to the focal point of a converging lens the image gets bigger. (ii) When the object is placed farther away from the converging lens, the image gets smaller. (iii) When the object is placed very far away from the converging lens, the image distance approaches focal length.
Which of the following statements is FALSE? 1. Focal length of a convex lens is positive. 2. Focal length of a concave lens is negative. 3. All measurements to the right of the optic centre are positive. 4. All measurements to the left of the optic centre are positive. 
Consider the following statements: A real image 1) Can be formed on a screen 2)  Is always magnified and inverted Which of the statements given above is/are correct?