Bissoy.com
Doctors Medicines MCQs Q&A

A convex lens of refractive index 1.49 is immersed in a certain liquid. For the lens to act as a transparent plane sheet, what should be the refractive index of the liquid?

A convex lens of refractive index 1.49 is immersed in a certain liquid. For the lens to act as a transparent plane sheet, what should be the refractive index of the liquid? Correct Answer 1.49

The correct answer is option 3) i.e. 1.49

CONCEPT:​

  • Transparent materials: Objects that allow light to pass through them and help see things clearly through them are called transparent materials.
  • Refraction: It is the phenomenon of bending of light rays when it travels from one transparent medium into another transparent medium, due to differences in speed of light in different media.
    • The speed of light reduces when light enters from a rarer to a denser medium and increases when light enters from a denser to a rarer medium.

​EXPLANATION:

  • In a transparent plane sheet, the thickness of the sheet is negligibly small that it allows light to travel through it with negligible deviation.
  • The speed of light varies in different media.
  • For a lens to act as a transparent sheet when placed in liquid refraction should not take place. So, either its thickness must be negligibly small or the speed of light in the liquid and lens must be the same.
  • The former is not possible, as the lens cannot be altered to a thin sheet.
  • Hence, the speed of the light in the lens must match that in the liquid. This is possible only if the two media have the same optical density i.e. refractive index.
  • Thus, the refractive index of the liquid must be equal to that of the lens i.e. 1.49.

Related Questions

Consider the following statement: A ray of light passing through the optical centre of a convex lens emerges without any deviation after refraction. A ray of light passing through the first principal focus of a convex lens  emerges parallel to the principal axis after refraction. A ray of light passing through the optical centre of a convex lens emerges parallel to the principal axis after refraction. Which one of the following statements INCORRECT?
Choose the correct relation for a combination of two prisms to be achromatic. (Where for the first prism: μv = refractive index of the medium in violet light, μr = refractive index of the medium in red light A = angle of the prism; For the second prism: μ′v = refractive index of the medium in violet light, μ′r = refractive index of the medium in red light, A’ = angle of prism.)
 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
Which of the following distinguishes section 34 of Indian Penal Code from section 149, Indian Penal Code?
1. Section 149 creates a substantive offence whereas section 34 does not create an offence.
2. Section 149 requires common object whereas section 34 requires common intention.
3. Section 149 requires five or more persons whereas section 34 requires two or more persons.
Select the correct answer:
Consider the following statements:
1. Section 34 of Indian Penal Code requires two persons whereas Section 149 of Indian Penal Code require five persons.
2. Section 34 of Indian Penal Code requires common intention, whereas Section 149 of Indian Penal Code requires common object
3. Section 34 of Indian Penal Code and Section 149 of Indian Penal Code both require presence of a prior consent
4. Section 34 of Indian Penal Code and section 149 of Indian Penal Code. Both create specific offence
Which of the above statements are correct?
Which of the following statement/statements is/are not correct?
1. Both Sections 34 and 149 of Indian Penal Code itself create specific offences
2. Both Sections 34 and 149 of Indian Penal Code relate to Doctrine of Vicarious liability
3. Section 34 fixes a minimum two persons who must share common intention while Section 149 requires there must be at least 10 persons to have the common object
4. Some active participation is necessary under Section 34 but Section 149 does not require it. Mere member of the unlawful Assembly with common object is sufficient for liability.
Carefully read following statements:
1. According to Section 34 of Indian Penal Code, requirement is of two persons, whereas under Section 149 of Indian Penal Code, requirement is of five persons.
2. According to Section 34 of Indian Penal Code, common intention is required whereas under Section 149 Indian Penal Code, common object is required
3. Previous consent is required under Section 34 & 149 of Indian Penal Code
4. Section 34 of Indian Penal Code and Section 149 of Indian Penal Code constitutes a specific offence
Which of the above statements is true:
The depth of centre of pressure (h) for a vertically immersed surface from the liquid surface is given by (where IG = Moment of inertia of the immersed surface about horizontal axis through its centre of gravity, A = Area of immersed surface, and x = Depth of centre of gravity of the immersed surface from the liquid surface)
The depth of centre of pressure (h) for a vertically immersed surface from the liquid surface is given by (where $${I_{\text{G}}}$$ = Moment of inertia of the immersed surface about horizontal axis through its centre of gravity, A = Area of immersed surface and x = Depth of centre of gravity of the immersed surface from the liquid surface)
Match the following (a) Concave mirror (i) A diverging lens (b) Concave lens (ii) Magnifying glass (c) Convex mirror (iii) Dentist mirror (d) Convex lens (iv) Rear view mirror