2nd Year Chemistry Chapter 18 Test18. Spectroscopy

Q1. Multiple choice questions (Attempt all · 10 × 1 = 10)

1. Spectroscopy is based on the interaction of atoms or molecules with:
   1. Heat
   2. Sound waves
   3. Electromagnetic radiations
   4. Chemical reactions
2. The property that makes nuclei NMR active is called:
   1. Isotopic mass
   2. Spin
   3. Charge density
   4. Energy difference
3. Which isotopes are commonly used in NMR studies?
   1. H¹ and C¹²
   2. H¹ and C¹³
   3. O¹⁶ and N¹⁴
   4. H² and C¹⁴
4. Why is ¹³C NMR possible while ¹²C NMR is not?
   1. ¹²C is radioactive
   2. ¹³C has non-zero nuclear spin
   3. ¹³C is more abundant
   4. ¹²C has strong magnetic properties
5. The typical IR range used for organic compounds is:
   1. 200–400 cm⁻¹
   2. 4000–625 cm⁻¹
   3. 10000–5000 cm⁻¹
   4. 1–100 cm⁻¹
6. Approximately what percentage of natural carbon atoms are ¹³C?
   1. 0.0001
   2. 0.01
   3. 0.1
   4. 0.5
7. Spectroscopy is a technique in which matter interacts with:
   1. Light
   2. Sulphuric acid
   3. Magnetic field
   4. Plasma
8. An atomic absorption spectrum is produced when atoms in the ground state:
   1. Emit light at specific wavelengths
   2. Absorb light at specific wavelengths
   3. Scatter incoming radiation
   4. Reflect visible light
9. In Atomic Emission Spectroscopy (AES), spectral lines appear as:
   1. Dark lines on bright background
   2. Bright lines on dark background
   3. Coloured bands
   4. Continuous spectrum
10. The energy difference between the two spin states corresponds to:
    1. X-ray frequency
    2. UV frequency
    3. Radio wave frequency
    4. Infrared frequency