To solve this problem it is necessary to apply the related concepts to the principle of overlap, specifically to single slit diffraction experiment concept.
Mathematically this can be expressed as:
![dsin\theta = m\lambda](https://img.qammunity.org/2020/formulas/physics/college/ootrughoga8l6dz2jletrqhscpip98ur7w.png)
Where,
d = Width of the slit
Wavelength
Angle relative to the original direction of the light
m = Any integer which represent the order of the equation (number of repetition of the spectrum)
To solve the problem we need to rearrange the equation and find the wavelength
![\lambda = (dsin\theta)/(m)](https://img.qammunity.org/2020/formulas/physics/college/46vreli5ro1lgpftahkvgmuyxkokncqyl0.png)
Our values are given as,
![d = 1.46\mu m = 1.46*10^(-6)m](https://img.qammunity.org/2020/formulas/physics/college/jx507a4tq17ehivy7gbt3pve7d7ydn1pw9.png)
![\theta = 21\°](https://img.qammunity.org/2020/formulas/physics/college/85cjkvzn81w2a9tojczadapndfu6colflz.png)
![m = 1](https://img.qammunity.org/2020/formulas/mathematics/middle-school/k7lrbgxf1du1kcww21jm7pwqddclr5uume.png)
Replacing in our equation we have,
![\lambda = (dsin\theta)/(m)](https://img.qammunity.org/2020/formulas/physics/college/46vreli5ro1lgpftahkvgmuyxkokncqyl0.png)
![\lambda = ((1.46*10^(-6))sin(21))/(1)](https://img.qammunity.org/2020/formulas/physics/college/ui3k3bxulxop0mw8h50hrdnp3lllfie6tr.png)
![\lambda = 5.232*10^(-7)m](https://img.qammunity.org/2020/formulas/physics/college/951ry268624hnmtfi3fy0ml9t4fefh8tq0.png)
![\lambda = 523.2nm](https://img.qammunity.org/2020/formulas/physics/college/6a98r5eljl0k714yqaucbw025iph2uggfa.png)
Therefore the wavelength is 523.2nm