Answer:
b)3:2
Explanation:
The dispersive power is the reciprocal of the focal length:
[tex]P=\frac{1}{f}[/tex]
Given the ratio of focal lengths:
[tex]\frac{f_1}{f_2} = \frac{2}{3}\\\\\frac{\frac{1}{P_1}}{\frac{1}{P_2}}=\frac{2}{3}\\\\\frac{P_2}{P_1}=\frac{2}{3}\\\\\frac{P_1}{P_2}=\frac{3}{2}[/tex]
Therefore,
Pā : Pā = 3 : 2
Hence, the correct option is:
b)3:2
