First order X-ray reflection `(lambda=154pm)` is maximum from a set of (2,0,0) planes of a bcc lattice was observed at `16^(0)6^(1)`. Then the edge length of unit cell is `(Sin 16^(0)6^(1)=0.2773)`

Options

A. 360pm
B. 420pm
C. 560pm
D. 180ppm

Explanation

For first order reflection, n=1
`lambda=2d sin theta`
`d=(lambda)/(2 sin theta)=(154)/(2xx0.2773)=280` pm
`d_(((2,0,0)))=(alpha)/sqrt(2^(2)+0^(2)+0^(2))rArr a=2xx280=560` pm