Two Lenses, One with a Focal Length F₁ = +20

question 52

Multiple Choice

Two lenses, one with a focal length f₁ = +20 cm and the other with a focal length f₂ = -20 cm, are on the same axis and 60 cm apart as shown. A real object is 40 cm to the left of the first lens, as shown. The final image formed by this two-lens combination is

• A) real and 10 cm from the negative lens.
• B) virtual and 10 cm from the negative lens.
• C) at infinity.
• D) virtual and 20 cm from the negative lens.
• E) None of these is correct.

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Definitions:

Conscious Processing

The mental activities of which an individual is aware, involving thoughts, perceptions, and feelings that are actively being thought about or manipulated.

Unconscious Processing

Mental processes that occur without conscious awareness, influencing perceptions, thoughts, and behaviors.

Fast and Effortless

Activities or processes that are completed quickly and with minimal mental or physical exertion.

Mind-Body Problem

The difficulty in understanding how the mind and body influence each other—so that physical events can cause mental events, and so that mental events can cause physical ones.