Light passes through a 0.15 mm-wide slit and forms a diffraction pattern on a screen 1.25 m behind the slit. The width of the central maximum is 0.75 cm. What is the wavelength of the light

The value is  

Explanation:

From the question we are told that

   The width of the slit is  

     The distance of the screen from the slit is D = 1.25 m

      The width of the central maximum is

Generally the width of the central maximum is mathematically represented as

Here  m is the order of the fringe and given that we are considering the central maximum, the order will be  m =  1  because the with of the central maximum separate's the and first maxima

So

=>    

=>    

=>      

what do the notation's look like?

f=ma newton's second law 7x8=56n