Advertisements
Advertisements
Question
What is presbyopia?
Solution 1
This defect is similar to hypermetropia i.e., a person having this defect cannot see nearby objects distinctly, but can see distant objects without any difficulty. This defect occurs in elderly persons (aged persons).
Solution 2
Presbyopia is a vision disorder that develops with age, usually beyond 40. This condition causes a progressive loss of visual focus on close objects.
RELATED QUESTIONS
Answer the following question in detail.
Define and describe the magnifying power of an optical instrument.
Answer the following question in detail.
How does magnifying power differ from linear or lateral magnification?
Answer the following question in detail.
What is a terrestrial telescope and an astronomical telescope?
Answer the following question in detail.
What is the limitation in increasing the magnifying powers of a compound microscope?
Answer the following question in detail.
What is the limitation in increasing the magnifying powers of the astronomical telescope?
Why is oil-immersed objective preferred in a microscope?
What are the advantages and disadvantages of using a reflecting telescope?
What are the uses of spectrometer?
What is the remedy of myopia?
What is the remedy of hypermetropia?
Obtain the equation for resolving the power of the microscope.
Explain the preliminary adjustments of the spectrometer.
Explain the experimental determination of the material of the prism using a spectrometer.
A light wave of wavelength λ is incident on a slit of width d. The resulting diffraction pattern is observed on a screen at a distance D. If linear width of the principal maxima is equal to the width of the slit, then the distance D is
An object viewed from a near point distance of 25 cm, using a microscopic lens with magnification '6', gives an unresolved image. A resolved image is observed at infinite distance with a total magnification double the earlier using an eyepiece along with the given lens and a tube of length 0.6 m, if the focal length of the eyepiece is equal to ______ cm.
Magnification produced by astronomical telescope for normal adjustment is 10 and length of telescope is 1.1 m. The magnification when the image is formed at least distance of distinct vision (D = 25 cm) is ______.
An observer looks at a distant tree of height 10 m with a telescope of magnifying power of 20. To the observer the tree appears:
In the adjoining figure, AB represents the incident ray, and BK is the reflected ray. If angle BCF = θ, then ∠BFP is given by ______.
A camera objective has an aperture diameter of d. If the aperture is reduced to diameter d/2, the exposure time under identical conditions of light should be made ______.
