Power of Lens
Physics ⇒ Light and Optics
Power of Lens starts at 10 and continues till grade 12.
QuestionsToday has an evolving set of questions to continuously challenge students so that their knowledge grows in Power of Lens.
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When you play a quiz, your answers are evaluated in concept instead of actual words and definitions used.
See sample questions for grade 11
A lens has a power of +5 D. What type of lens is it?
Define the power of a lens and state its SI unit.
Describe how the power of a lens changes if its focal length is doubled.
Explain the significance of the sign of the power of a lens.
Explain why the power of a concave lens is negative.
A student combines a +4 D lens and a -6 D lens. What is the resulting power?
A convex lens of power +4 D is placed in contact with a concave lens of unknown power. The combination has a focal length of 1 m. Calculate the power of the concave lens.
A lens forms a virtual image at a distance of 40 cm from the lens when the object is placed 20 cm from it on the same side. Calculate the power of the lens.
A lens is marked as +6 D. If a student accidentally uses it as a diverging lens in an experiment, what type of error will occur in the image formation? Explain.
Which lens would you use to correct hypermetropia (farsightedness)?
(1) Lens with positive power
(2) Lens with negative power
(3) Lens with zero power
(4) None of the above
Which of the following is the correct formula for the power of a lens?
(1) P = f
(2) P = 1/f
(3) P = 2f
(4) P = f/2
Which of the following lenses has the greatest power?
(1) f = +10 cm
(2) f = +20 cm
(3) f = -10 cm
(4) f = -20 cm
Which of the following statements is correct?
(1) A lens with positive power is always convex.
(2) A lens with negative power is always concave.
(3) Both (1) and (2)
(4) None of the above
Fill in the blank: The SI unit of power of a lens is ______.
If the focal length of a lens is 25 cm, its power is ______ D.
If the power of a lens is doubled, its focal length becomes ______ of its original value.
True or False: The higher the power of a lens, the shorter its focal length.
True or False: The power of a diverging lens is always negative.
True or False: The power of a lens is inversely proportional to its focal length.
A student claims that a lens with a shorter focal length always has a higher power, regardless of whether it is convex or concave. Is this statement true or false?
