The radial force on the particle is given by the Lorentz force. They don't give you the velocity so you have to solve for it in terms of the radius and get them to cancel.

6 0

3 years ago

One day, after pulling down your window shade, you notice that sunlight is passing through a pinhole in the shade and making a s

baherus [9]

Given that,

Central maximum = 1 cm

Distance from the window shade to the wall =4 m

We know that,

The visible range of the sun light is 400 nm to 700 nm.

(a). We need to calculate the average wavelength

Using formula of average wavelength

$\lambda_{avg}=\dfrac{\lambda_{1}+\lambda_{2}}{2}$

Put the value into the formula

$\lambda_{avg}=\dfrac{400+700}{2}$

$\lambda_{avg}=550\ nm$

(b). We need to calculate the diameter of the pinhole

Using formula for diameter

$w=\dfrac{2.44\lambda L}{D}$

$D=\dfrac{2.44\lambda L}{w}$

Put the value into the formula

$D=\dfrac{2.44\times550\times10^{-9}\times4}{1\times10^{-2}}$

$D=0.537\ mm$

Hence, (a). The average wavelength 550 nm.

(b). The diameter of the pinhole is 0.537 mm.

7 0

3 years ago