A Lens Is Made of Glass of Index of Refraction

question 60

Multiple Choice

A lens is made of glass of index of refraction 1.60. If both the surfaces are convex and the radii of curvatures are 10 cm and 20 cm, the focal length of the lens in air is

• A) 11.1 cm.
• B) -11.1 cm.
• C) 25 cm.
• D) 33.3 cm.
• E) -33.3 cm.

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Definitions:

Life Instincts

In psychoanalysis, these are the drives or instincts that are directed towards preservation and enhancement of life, including basic needs such as hunger and sex.

Death Instincts

In Freudian psychology, innate drives or impulses leading towards aggression, self-destruction, and death, opposed to life-sustaining instincts.

Human Instincts

Innate, typically fixed patterns of behavior in animals or humans in response to certain stimuli.

Repression

A defense mechanism where unwanted or discomforting thoughts and memories are unconsciously pushed from the conscious mind.