Question

What voltage must be applied to an X-ray tube for it to emit X-rays with a minimum wavelength of 30 pm?

Answer 1

This can be solve by this way:

As you should know, the problem is referring to pm wavelengths.

So, λ=30*10⁻¹²m

We take the formula that says:

λ(min)=$\frac{1.24*10⁻⁶ v.m}{V(max)}$, then

V(max)= $\frac{1.24*10⁻⁶ v.m}{λ(min)}$, making the values substitution

V(max)= $\frac{1.24*10⁻⁶ v.m}{30*10⁻¹²m}$

V(max)= 4.13*10⁴ v