answer in short
State the laws of magnetism.
2. Why are big indoor auditoriums carpeted and their walls are coated with
rough materials?
3. How can a magnet lose its properties?
4. State the laws of reflection of sound.
5. State the speed of sound in : (i)air (ii) water
Answers
Answer:
1. A basic law of magnetism is that unlike poles attract each other. Two bar magnets can illustrate this.
2. Cinema halls and audutoriums are carpeted and the walls are made of rought material, because these materials absorb the sound and do not allow them from going out of as, some times the sound can be a trouble to the people.
3. Elevated temperature: Magnetic materials lose magnetism as they heat, but they regain magnetism when cooled provided the maximum temperature is below their Curie temperature.
4. The law of reflection of sound waves states that the angle of incidence is always equal to the angle of reflection. But unlike reflection of light on a highly smooth surface, in the reflection of the sound wave, a part of the incident wave gets transmitted to the medium where it hits.
5. The speed of sound in air under typical conditions is about 343 meters per second, while the speed of sound in water is about 1,480 meters per second. Fundamentally, standard sound is a compression wave traveling though a material.