# Ray Optics: Refraction and Lenses

## Refraction and Lenses: Audio Guided Solution

#### Problem 31:

Matthew's new Bug Habitat toy comes with a built in magnifier, allowing Matthew to get a close-up view of his captive ants, crickets, slugs, and other creatures. The magnifier has a focal length of 22 cm. Determine the distance which an ant must be located from the lens in order for it to appear magnified by a factor of 12.

## Habits of an Effective Problem Solver

• Read the problem carefully and develop a mental picture of the physical situation. If necessary, sketch a simple diagram of the physical situation to help you visualize it.
• Identify the known and unknown quantities and record them in an organized manner. Equate given values to the symbols used to represent the corresponding quantity - e.g., do = 24,8 cm; di = 16.7 cm; f = ???.
• Use physics formulas and conceptual reasoning to plot a strategy for solving for the unknown quantity.
• Identify the appropriate formula(s) to use.
• Perform substitutions and algebraic manipulations in order to solve for the unknown quantity.