Spherical Lenses

Given: The power of the lens is . Step 1: Use the formula for power The formula for the power of a lens is: where is the power in diopters, and is the focal length in meters. Step 2: Rearrange the formula and solve for Rearranging the formula to find the focal length: Step 3: Substitute the value of Substitute into the formula: Answer: The correct answer is option (1): 0.5 m.

Given: The focal length of the lens is and the object distance is (since the object is placed on the left of the lens, we take it as negative). Step 1: Use the lens formula The lens formula is given by: where: - is the focal length of the lens, - is the image distance, - is the object distance. Step 2: Solve for Rearranging the lens formula to solve for : Substitute and : Thus, Step 3: Calculate the magnification The magnification is given by: Since the question asks for the magnification produced when the object is 30 cm from the lens, the answer is 1.5. Answer: The correct answer is option (2): 1.5.