# Questions on Crystal Diffraction and Answers

## Questions on Crystal Diffraction and Answers

Q1. In the X-ray diffraction pattern of a sodium metal, which has a BCC structure, the missing reflection planes will be

• (A) 101
• (B) 011
• (C) 020
• (D) 100

Q2. A metal with body centered cubic (bcc) structure shows the first (i.e, smallest angle) diffraction peak at a Bragg angle of θ = 30°. The wavelength of X-ray used is 2.1 Å. The volume of the unit cell of the metal is

• (A) 9.3 (Å)3
• (B) 26.2 (Å)3
• (C) 13.1 (Å)3
• (D) 4.6 (Å)3

Q3. Consider X-ray diffraction from a crystal with a face centered cubic (fcc) lattice. The lattice plane for which there is no diffraction peak is

• (A) (2, 1, 2)
• (B) (2, 0, 0)
• (C) (1, 1, 1)
• (D) (3, 1, 1)

Q4. For a NaCl crystal, the cell-edge a = 0.563 nm. The smallest angle at which Bragg reflection can occur corresponds to a set of planes whose indices are

• (A) (100)
• (B) (110)
• (C) (111)
• (D) (200)

Q5. The distance between the adjacent atomic planes in CaCO3, is 0.3 nm. The smallest Bragg scattering for 0.03 nm X-ray is

• (A) 2.9°
• (B) 1.5°
• (C) 0.29°
• (D) 5.8°

Q6. An X-ray tube operated at 30 kV emits a continuous X-ray spectrum. The short wavelength limit λ (given that e = 1.6 × 10-19 coulomb, c = 3 ×108 m/sec and h = 6.624 ×10-34 J-sec) is given by

• (A) 0.1656 nm
• (B) 0.0414 nm
• (C) 0.0207 nm
• (D) 0.2040 nm

Q7. The wavelength associated with an electron accelerated through a potential difference 100 V is

• (A) 1.2 Å
• (B) 12.2 Å
• (C) 12 nm
• (D) 1.22 pm

Q8. X-rays can be deflected by

• (A) magnetic field
• (B) only electric field
• (C) only simultaneously applying electric and magnetic field
• (D) neither by electric nor magnetic field

Q9. The number of ions in the unit cell of NaCl crystal is

• (A) 1
• (B) 4
• (C) 8
• (D) 2

Q10. The angle of diffracted X-rays is 90° from the incident direction of X-rays. The interplanar separation of the planes responsible for the diffraction is given by

• (A)  λ/√2
• (B) λ/2
• (C) λ√2
• (D) (λ√3)/2

Q11. Characteristic X-rays are the characteristic of which of the following :

• (A) Cathode materials
• (B) Accelerating voltage
• (C) Anode materials
• (D) Tube current

Q12. X-ray diffraction can be applied to

• (A) liquids only all liquids,
• (B) solids and crystalline materials
• (C) gaseous or vapour materials only
• (D) solid, crystalline materials only

Q13. The amplitude of scattering of X-rays scattered by a single atom is generally denoted as

• (A) Polarization factor
• (B) Form factor
• (C) Structure factor
• (D) Fractional coordination

Q14. During X-ray emission if the voltage is increased:

• (A) minimum wavelength decreases
• (B) intensity increases
• (C) minimum wavelength increases
• (D) intensity decreases

Q15. In the X-ray diffraction of a set of crystal planes having d equal to 0.18 nm, first order reflection is found to be at an angle of 22° . The wavelength of X-ray is: (sin 22° = 0.208) :

• (A) 0.0749 nm
• (B) 0.0374 nm
• (C) 0.749 nm
• (D) 0.374 nm

close