To determine the magnification of a compound microscope given the focal lengths of the objective and eyepiece, as well as the distance at which the image is formed, we can use the formula for magnification in a compound microscope. The magnification (M) is the product of the magnification of the objective (Mo) and the magnification of the eyepiece (Me).
Understanding the Components
In this scenario, we have:
- Focal length of the objective (fo): 5 cm
- Focal length of the eyepiece (fe): 10 cm
- Image distance from the objective (v): 15 cm
Calculating the Objective Magnification
The magnification of the objective (Mo) can be calculated using the formula:
Mo = v / (v - fo)
Substituting the values:
Mo = 15 cm / (15 cm - 5 cm) = 15 cm / 10 cm = 1.5
Calculating the Eyepiece Magnification
The eyepiece magnification (Me) is calculated using the formula:
Me = D / fe
Where D is the near point distance, typically taken as 25 cm for a relaxed eye. Thus:
Me = 25 cm / 10 cm = 2.5
Finding Total Magnification
The total magnification (M) of the compound microscope is the product of the objective and eyepiece magnifications:
M = Mo × Me
Substituting the values we calculated:
M = 1.5 × 2.5 = 3.75
Revisiting the Problem
It seems there might be a misunderstanding regarding the values or the setup, as the calculated magnification does not match any of the options provided (6, 7, 8, or 9). It's essential to ensure that the distances and focal lengths are correctly interpreted and applied. If the image distance or any other parameters were different, it could lead to a different magnification result.
Final Thoughts
In practical terms, if you were to adjust the parameters or clarify any additional details about the setup, we could re-evaluate the magnification. Understanding how each component of the microscope contributes to the overall magnification is crucial for effective use and analysis.