In young's double slit experiment the slits are illumated by light of wavelength `5890^(@)` A and the distance between the fringes obtained on the screen is `0.2^(@)`. If the whole apparatus is immersed in water then the angular fringe width will be, if the refractive index of water is `4//3`

Explanation

`alpha_(air)=lamda/d impliesalpha_(air)=0.2^@impliesa proplamdaimpliesalpha_w/alpha_(air)=lamda_(w)/lamda_(air)`
`implieslamda_w=lamda_(air)/mu=alpha_w=(alpha_(air)lamda)/(mulamda)=(0.2times3)/4=0.15^@`