Question

(1)a thick proper strit is used in a lighting conductor conductor? Give reason?

(2)Classify substances in sublimetary and non-sublimetary
1.sand
2.iodinge
3.sal ammonia
4.salt
5.alum
6.sugar
7.termeric
8.napthalene balls

Q. 2.A farmers spread a layer of cetyl alcohal on the surface of water of farm lakes? Why?
(a) boiling of water
(b) to stop evapuration of water
(c) to distroy marine animals
(d) to distroy alge from water


Q. 12. How will you separate to stamelene bowel that are stuck in each other
(a) By keeping in ice water
(b) by covering hot water in bowel
(c) by heating bowel on gas
(d(by keeping bowel in refegriator

Answer 1

Ans (1)  A lightning rod or lightning conductor is a metal rod mounted on a structure and intended to protect the structure from a lightning strike. Copper makes the best lightning conductor. Copper and its alloys are the most common materials used in lightning protection. While the electrical resistance of the lightning conductor between the air terminal and the Earth is of significant concern, the inductive reactance of the conductor could be more important. Therefore, Copper is the preferred conductor.

 

Ans (2). Sublimation is a specialized change of state when a solid substance skips the liquid phase and moves directly into the gas phase. Sublimatory substances – Iodine, Sal Ammonia, Naphthalene balls. Non-sublimatory substances - sand, salt, sugar, alum, and turmeric.

Ans. 2. The correct answer is the option (b) - to stop evaporation of water. Cetyl alcohol, also known as hexadecan-1-ol and palmityl alcohol, is a fatty alcohol which in non-soluble in water. Therefore, a monolayer is added on the reservoirs, dams etc. to prevent evaporation of water and to retain the heat.

Ans 12. The correct answer is option (a) - By keeping in ice water.