Question

What are the magnification formulas for the eyepiece when the final image is at the near point and when the final image is at infinity, respectively?

Options

• Near point: \[m_e = \left(1 + \frac{f_e}{D}\right)\]; Infinity: \[m_e = \left(\frac{f_e}{D}\right)\]

• Near point: \[m_e = \left(1 + \frac{D}{f_o}\right)\]; Infinity: \[m_e = \left(\frac{D}{f_o}\right)\]

• Near point: \[m_e = \left(\frac{D}{f_e}\right)\]; Infinity: \[m_e = \left(1 + \frac{D}{f_e}\right)\]

• Near point: \[m_e = \left(1 + \frac{D}{f_e}\right)\]; Infinity: \[m_e = \left(\frac{D}{f_e}\right)\]

Answer 1

For the eyepiece, when the final image is at the near point, \[m_e = \left(1 + \frac{D}{f_e}\right)\]. When the final image is at infinity, \[m_e = \left(\frac{D}{f_e}\right)\]. The near point case gives a magnification one more than the infinity case.