When 40 kV is applied across an X-ray tube, X-ray is obtained with a maximum frequency of `9.7 xx 10 ^18` Hz. Calculate the value of Planck constant from these data.

Explanation

To calculate the value of Planck's constant (h) using the given data from the X-ray tube, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Given Data:**
- Maximum frequency of X-ray, \( \nu_{\text{max}} = 9.7 \times 10^{18} \, \text{Hz} \)
- Voltage applied across the X-ray tube, \( V = 40 \, \text{kV} = 40 \times 10^3 \, \text{V} \)

...