The refractive indices of flint glass prisms for C, D, and F lines are 1.790, 1.795, and 1.805 respectively. The dispersive power of the flint glass prism is:
A) 0.141
B) 0.125
C) 0.018
D) 0.929

The dispersive power of a material is defined as the ratio of the difference in refractive indices for two different lines of light (usually the F and C lines) to the mean refractive index for a particular set of lines.

The formula for dispersive power (ω) is:

ω = (n_F - n_C) / (n_D - 1)

Where:

n_F is the refractive index for the F line (which is 1.805)
n_C is the refractive index for the C line (which is 1.790)
n_D is the refractive index for the D line (which is 1.795)
Now, let's calculate the dispersive power:

First, find the difference between the refractive indices for the F and C lines: n_F - n_C = 1.805 - 1.790 = 0.015

Next, find the difference between the refractive index for the D line and 1: n_D - 1 = 1.795 - 1 = 0.795

Now, calculate the dispersive power: ω = 0.015 / 0.795 ≈ 0.0188

Rounding to three decimal places, we get ω ≈ 0.018.

Thus, the dispersive power of the flint glass prism is approximately 0.018, which corresponds to option C.

So, the correct answer is: C) 0.018