Elementary Optics

A lens is an optically transparent medium bounded by two spherical _______ surfaces or one plane or one spherical surface.

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Tags

NGSS.HS-PS4-1

NGSS.HS-PS4-5

Which lens is thicker at the centre and thinner at the edges

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When an object is at infinity, a real image is formed at the _____

• Principal focus

• Center of curvature

• Between principal focus and centre of curvature

• Beyond Principal focus

When an object is placed ____, the size of the image is same as that of the object

• Between F and C

• At Principal focus

• At C

• Between the Principal focul and Optical centre

Convex and Concave lens used to correct ______ and ____ respectively.

• Myopia, Hypermeteropia

• Hypermeteropia, Myopia

• Myopia, Predyopia

The size of the image formed increases as the distance between the object and the lens is _____

• Increased

• Decreased

• Same

Where should an object be placed so that a real and inverted image is formed behind the center of the curvature

• Between F and 2F

• F

• 2F

• infinity

A small bulb is placed at the principal focus of a convex lens. When the bulb is switched on the lens will produce ____

• A convergent beam of light

• A divergent beam of light

• A parallel beam of light

• A colored beam of light

A converging lens is used to form an image on a screen, when upper half of the lens is covered by an opaque screen

• Half of the image will disappear

• Complete image will be formed of same intensity

• Complete image will be formed of decreased intensity

• Half of the image will be formed of same intensity

A lens is said to be converging if the width of the beam _____ after refraction through it

• Increases

• Decreases

• Same