Chapter 12: Electromagnetic Spectrum
SOLUTION OF SELF-ASSESSMENT QUESTIONS
12.1 Dispersion of Light
Q1: A ray of blue light deviates more than a ray of red when passing through a prism. Explain why?
The amount of refraction of waves depends upon their wavelengths, the greater the wavelength less will be the refraction. The wavelength of blue light is smaller than that of red light, which is why blue light deviates more than red light when passing through a prism.
Q2: Give the sequence of colors produced in the dispersion through a prism.
The order of colors from the base of a prism is violet, indigo, blue, green, yellow, orange, and red. The sequence of colors is indicated by the acronym VIBGYOR.
Q3: X-rays have a higher frequency than radio waves. What is their speed in space?
All electromagnetic waves travel in free space with the same speed of 3x108 m/s, irrespective of their frequency.
12.2 Characteristics of Electromagnetic Waves
Q1: State two different components of the electromagnetic spectrum that have wavelengths more significant than the wavelengths of red light.
Infrared, microwaves and radio waves are the different components of the electromagnetic spectrum that have wavelengths more significant (greater) than the wavelengths of red light.
Q2: State at least four properties common to all electromagnetic waves.
- Electromagnetic waves are transverse in nature.
- They are composed of varying electric and magnetic fields that oscillate perpendicularly. The direction of wave motion is perpendicular to both electric and magnetic fields.
- They do not carry an electric charge.
- All electromagnetic waves travel through a vacuum at a speed of 3x10^8 m/s.
12.3 Uses of Electromagnetic Waves
Q1: State health risks associated with high energy components of electromagnetic radiations.
In fair skin, the UV rays can penetrate deeper and are harmful to live cells. Excess ultraviolet exposure can result in several skin diseases.
Q2: What is the advantage of optical fibers in telecommunication over copper cables?
Compared to copper wires, fiber optics cables are lighter, more flexible, and carry more data. The speed and accuracy of the transmission data are much better in fiber optics.
Q3: State the role played by gamma radiations in radiosurgery.
Gamma rays are used in gamma knife radiosurgery. It is a medical procedure that uses gamma rays to destroy small tumors in the brain with less damage to surrounding cells.
Chapter 12: Electromagnetic Spectrum
MCQs | Notes | Numerical | Self Assessment Questions
0 Comments