Two small angled prisms A and B deviate the blue rays by `7^@` and `9^@` and the red rays by `5^@` and `7^@` respectively. Which prism has a greater dispersive power?

Explanation

To determine which prism has a greater dispersive power, we can use the formula for dispersive power (ω):

\[ \omega = \frac{\text{Angular Dispersion}}{\text{Mean Deviation}} \]

### Step 1: Calculate the dispersive power for prism A

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