330. The PVC doors and windows are preferred as they are
A. rust proof
B. rot proof
C. termile proof
D. all of these.

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331. Based on flow quality, the sequence of pipes is
A. A.C. pipes, G.I. pipes, C.I. pipes, PVC pipes
B. C.1. pipes, G.I. pipes, A.C. pipes, PVC pipes
C. C.I. pipes, G.I. pipes, PVC pipes, A.C. pipes
D. None of these.

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332. The most commonly used synthetic abrasive is
A. aluminium carbide
B. boric acid
C. silicon
D. All of these.

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333. Pick up the synthetic resin from the following :
A. Malamine resin
B. Phenolic resin
C. Resorcinol resir
D. All of these.

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334.  Asbestos
A. is a natural fibrous mineral substance
B. is composed of hydrous silicates of calcium and mag nesium (CaSiO3, 3MgSiO3)
C. contains iron oxide and alumina
D. all the above.

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335. Which one of the following is acid resistant asbestos:
A. actinolite asbestos
B. amosite asbestos
C. anthophylite asbestos
D. All the above.

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336. Non acid-resistant asbestos is :
A. tremolite asbestos
B. chrysolite asbestos
C. amosite absestos
D. none of these.

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