Science Practice Quiz 87

Q1.Which of the following are mentioned as examples of lenses in the provided text?

A. Microscope slides and telescope mirrors. B. Glasses used in spectacles and that by a watchmaker. C. Camera lenses and projector screens. D. Window panes and car windshields.

Q2.What happens to a ray of light that passes through the optical centre of a lens?

A. It deviates significantly B. It is reflected back C. It passes without suffering any deviation D. It converges to a point

Q3.What is the effective diameter of the circular outline of a spherical lens called?

A. Focal length B. Radius of curvature C. Optical centre D. Aperture

Q4.Which condition defines a 'thin lens with small apertures'?

A. Its aperture is much greater than its radius of curvature B. Its two centres of curvatures are far from the optical centre C. Its aperture is much less than its radius of curvature and its two centres of curvatures are equidistant from the optical centre D. Its focal length is equal to its radius of curvature

Q5.When parallel rays of light from the Sun are incident on a convex lens, what happens to them?

A. They diverge B. They are absorbed C. They are reflected D. They are converged by the lens at a sharp bright spot

Q6.What type of image of the Sun is formed on a sheet of paper when a convex lens converges sunlight?

A. A virtual image B. A magnified image C. A real image D. An inverted image

Q7.Why does paper begin to burn when a convex lens focuses sunlight onto it, according to the activity described?

A. The lens absorbs all the light B. The paper is highly flammable C. The concentration of the sunlight at a point generated heat D. The lens reflects heat onto the paper

Q8.For a convex lens, what is the point on the principal axis called where parallel rays of light converge after refraction?

A. Optical centre B. Centre of curvature C. Principal focus D. Focal point

Q9.For a concave lens, what is the point on the principal axis called from which parallel rays of light appear to diverge after refraction?

A. Optical centre B. Principal focus C. Centre of curvature D. Focal point

Q10.How many principal foci does a lens typically have?

A. One B. Two C. Three D. Four

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Science Practice Quiz 87