Question

For a lens immersed in a medium of refractive index \[n_1\], the power is related to the focal length by:

Options

• \[P = \frac{n_1}{f}\]

• \[P = \frac{n_2}{f}\]

• \[P = n_1 f\]

• \[P = \frac{1}{n_1 f}\]

Answer 1

When the lens is immersed in a medium of refractive index \[n_1\], the power is \[P = \frac{n_1}{f}\]. This is the power of the lens in that surrounding medium.