Electromagnetic Spectrum

Step 1: Concept
Electromagnetic (EM) waves consist of oscillating electric and magnetic fields and travel at the speed of light.
Step 2: Analysis
X-rays, -rays, and microwaves are all part of the EM spectrum. -rays, however, are fast-moving electrons or positrons.
Step 3: Conclusion
-rays are particulate radiation, not electromagnetic waves.
Final Answer: (C)

Step 1: Rearranging for Binomial Form
.
Step 2: Expanding


Step 3: Finding Constant Term
Constant term = .
Final Answer: (d)

Step 1: Concept
Solar radiations are electromagnetic waves emitted by the sun.
Step 2: Analysis
All electromagnetic waves consist of oscillating electric and magnetic fields perpendicular to the direction of propagation.
Step 3: Conclusion
This makes them transverse in nature.
Final Answer: (A)

Step 1: Understand the nature of band spectra.
Band spectra are produced when molecules absorb light and undergo transitions between various energy states within the molecular orbitals. Unlike atomic spectra, which consist of discrete lines, band spectra appear as a series of closely spaced lines or bands.

Step 2: Characteristics of band spectra.
- Atoms produce line spectra, which are very sharp because electron transitions occur between fixed energy levels.
- Molecules, however, produce band spectra because the energy levels are more closely spaced and involve molecular vibrations and rotations in addition to electronic transitions.

Step 3: Conclusion.
Therefore, band spectra are characteristic of molecules, which involve more complex energy transitions than atoms.

Step 1: Understanding the Concept:
Dimensions: , , .
Step 2: Detailed Explanation:
.
Equating powers: For L: .
For T: .
Step 3: Final Answer:
Thus, .

Concept: Thermal radiation is emitted by all bodies due to their temperature and lies mainly in the infrared region.

Step 1: Nature of thermal radiation.
Hot objects emit radiation predominantly in infrared wavelengths.

Step 2: Conclusion.