For a crystal with λ = 1 Å and Bragg's angle θ = 60°, the second-order diffraction, 'd' (distance between two consecutive atomic layers) will be:
1.  1.15 Å
2.  0.75 Å
3.  0.55 Å
4.  2.1 Å

The interplanar distance in a crystal is \(2.8 \times 10^{-8} \) m. The value of the maximum wavelength which can be diffracted:

1. \(2.8 \times 10^{-8} \)$m$

2. \(5.6 \times 10^{-8} \)$m$

3. \(1.4 \times 10^{-8} \)$m$

4. \(7.6 \times 10^{-8} \)$m$