Question

Match List I with List II: 

List I (EM Wave)	List II (Production)
A. Microwave	I. Electronic transitions in atoms
B. Visible light	II. Radioactive decay of nucleus
C. Gamma rays	III. Vibration of atoms and molecules
D. Infra-red rays	IV. Klystron or magnetron valve

• A. A-III, B-I, C-II, D-IV
• B. A-III, B-IV, C-I, D-II
• C. A-IV, B-I, C-II, D-III
• D. A-IV, B-III, C-II, D-I

Hint:

To remember Infrared (IR), associate it with "Heat." Heat is the kinetic energy of vibrating molecules, which directly matches List II-III.

Answer 1

The Correct Option is C

Step 1: Understanding the Topic:
This question is based on "Electromagnetic Waves." The electromagnetic spectrum consists of waves with varying frequencies and wavelengths, each produced by different physical processes occurring at the atomic, molecular, or nuclear levels. Understanding these origins is key to understanding how we generate and detect various signals.
Step 2: Key Formulas and Approach:
The approach involves identifying the energy scales of the waves:
High energy (Gamma) comes from nuclear levels.
Medium energy (Visible) comes from atomic levels.
Low energy (Infrared/Microwave) comes from molecular or electronic circuit levels.

Step 3: Detailed Explanation:

Microwave (A $\rightarrow$ IV): Microwaves have wavelengths in the centimeter range. They are generated by oscillating currents in special vacuum tubes such as klystrons, magnetrons (like in a microwave oven), or Gunn diodes.
Visible Light (B $\rightarrow$ I): Visible light is emitted when electrons in an atom jump from a higher energy excited state to a lower energy state. This transition energy corresponds to the visible part of the spectrum.
Gamma Rays (C $\rightarrow$ II): These are the most energetic EM waves. They are produced by the transitions of nucleons within the nucleus during radioactive decay or nuclear reactions.
Infra-red Rays (D $\rightarrow$ III): Also known as heat waves, infrared radiation is produced by the thermal vibrations and rotations of atoms and molecules within a substance.
Matching these pairs, we find that Option (C) is the correct sequence.
Step 4: Final Answer:
The correct matching is A-IV, B-I, C-II, D-III.