In a two-slit experiment, laser light of wavelength $600\mathrm{nm}$ passes through a pair of slits separated by $42\mathrm{\mu }\mathrm{m}$. If the observing screen is $1.4\mathrm{m}$ from the slits, what is the separation, in mm, between the bright fringes?

• A. $10\mathrm{mm}$
• B. $15\mathrm{mm}$
• C. $25\mathrm{mm}$
• D. $30\mathrm{mm}$
• E. $35\mathrm{mm}$
• F. $20\mathrm{mm}$