Chapter 5 : Electromagnetic waves – Important 2 Mark Questions
Most Repeated 2 Mark Questions
Curated from Previous Year Question Papers
What is displacement current?
The displacement current can be defined as the current which comes into play in the region in which the electric field or the electric flux is changing with time .
What are electromagnetic waves?
What is meant by Fraunhofer lines?
When the spectrum obtained from the Sun is examined, it consists of a large number of dark lines (line absorption spectrum). These dark lines in the solar spectrum are known as Fraunhofer lines .
Give two uses each of (i) IR radiation, (ii) Microwaves and (iii) UV radiation.
- It provides electrical energy to satellites by means of solar cells.
- It is used to produce dehydrated fruits.
- It is used in greenhouses to keep the plants warm.
- It is used for heat therapy for muscular pain or sprain.
- It is used in TV remotes as a signal carrier.
- It is used to look through haze, fog or mist.
- It is used in night vision or infrared photography.
- They are used in radar systems for aircraft navigation and for measuring the speed of vehicles.
- They are used in microwave ovens for cooking.
- They are used for very long-distance wireless communication through satellites.
- It is used to destroy bacteria for sterilizing surgical instruments.
- It is used in burglar alarms.
- It is used to detect invisible writing and fingerprints.
- It is used in the study of atomic structure.
Give uses of X-rays.
X-rays are used extensively in studying the structures of inner atomic electron shells and crystal structures. They are also used in detecting fractures, diseased organs, formation of bones and stones, and observing the progress of healing bones.
Further, in a finished metal product, X-rays are used to detect faults, cracks, flaws and holes.
Appeared Once Questions
Curated from Previous Year Question Papers
Give uses of Gamma rays.
Write down the integral form of modified Ampere’s circuital law.
The total current enclosed by the surface becomes the sum of conduction current and displacement current.
