Ray Optics And Optical Instruments

Lens formula,
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or
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Step 1: Use the lens formula The lens formula relates the object distance ( ), image distance ( ), and focal length ( ): Step 2: Use the magnification formula The magnification ( ) produced by the lens is given by: Step 3: Substitute the given values into the lens formula Given: - , - (object distance is always negative in lens formula). Now, use the lens formula to find : Step 4: Calculate the magnification Now, use the magnification formula: The negative sign indicates that the image is inverted. Answer: Therefore, the magnification produced is , but the magnitude of the magnification is . So, the correct answer is option (1).

Step 1: Use the formula for the power of a lens The power of a lens is related to its focal length by the formula: where: - is the power of the lens (in diopters), - is the focal length of the lens (in meters). Step 2: Solve for Given that the power of the lens is , substitute this into the formula: Now, solve for : Answer: Therefore, the focal length of the lens is 0.5 m. So, the correct answer is option (1).