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MCQ
22241. The coefficient of hardness of stones used in road works should not be greater than : [PPA-20]
10
12
15
17
ব্যাখ্যা: The coefficient of hardness of stone between 14-17 for building purpose and greater than 17 is used for road.
22242. The maximum percentage of chemical ingredient of cement is that of- [PPA-19]
magnesium
iron oxide
aluminium
lime
ব্যাখ্যা: Lime percentage in cement 67%.
22243. What are the two main elements of Portland cement? [BREB-17, HED-19]
Lime & Silica
Lime & Iron
Lime & Alumina
Silica & Copper
ব্যাখ্যা: The elements of portland cement are lime or calcium oxide, silica, alumina, iron oxide, Magnesium oxide. But the main elements of portland cement are lime and silica.
22244. বড়র পীরিত বালির বাঁধ’ বাগধারাটির সঠিক অর্থ হচ্ছে-
চাপের মুখে ভেঙ্গে যায়
কোন বাধ্যবাধকতা নেই
একতরফা
ভঙ্গুর
22245. The clinker is formed at a temperature of-(MOD-20)
500°C
1000°C
1200°C
1500°C
ব্যাখ্যা: Portland cement clinker is made by heating a homogeneous mixture of raw materials in a rotary kiln at high temperature. The products of the chemical reaction aggregate together at their sintering temperature, about 1,500°C (2,732°F).
22246. Soundness of cement is tested by- [BB-20]
Vicats appararus
Le-chatelier apparatus
Compressive strength testing apparatus
none of these
ব্যাখ্যা: Soundness of cement may be determined by two methods, namely le-chatelier method and autoclave method, Soundness of cement is tested by le-chatelier apparatus.
22247. নিচের কোনগুলো অর্ধ-তৎসম শব্দ?
তুরূপ, রুইতন
চাহিদা, শিখ
আনারস, আলপিন
বোস্টম, গিন্নী
22248. Calculate standard consistency (%) when 100ml if water is added in 1kg of cement-----[BB-20]
10
1000
100
1
ব্যাখ্যা: Standard Consistency (%) = (wt of water added/wt of cement) x 100 =(100/1000)x100=10
22249. What is the specific gravity of cement? [MOD-20]
3.50
2.67
2.15
3.15
ব্যাখ্যা: The specific gravity is normally defined as the ratio between the weight of a given volume of material and weight of an equal volume of water. The portland cement have a specific gravity of value around 3.15. Specific gravity of cement is ranging between 3.1-3.16 g/cc.
22250. Le-chatelier apparatus used to perform- [BPSC-20]
Fineness test
Soundness test
Consistency test
Compressive strength test
ব্যাখ্যা: সিমেন্টের সাউন্ডনেস টেস্ট করা জন্য ব্যবহৃত যন্ত্রের নাম Le-chatelier apparatus.
22251. Which one is the fine aggregate? [MOD-20]
cement
sand
khoa
lime
ব্যাখ্যা: Sand, surki, stone screenings, burnt clays, cinders, fly ash etc. are used as fine aggregate in concrete.
22252. Geologically marble is known as- [PPA-19]
Sedimentary rock
Igneous rock
Metamorphic rock
Stratified rock
ব্যাখ্যা: Marble is a metamorphle rock (রূপান্তরিত শিলা) composed of recrystallized carbonate minerals, most commonly calcite or dolomite.
22253. Oil point-এর ক্ষেত্রে সাধারণত Solvent হিসাবে ব্যবহার করা হয়- [BPSC-20]
Linseed oil
Turpentine
Naptha
Kerosene
ব্যাখ্যা: Oil paint-এর সাথে Turpentine মিশ্রণের মাধ্যমে Paint- কে ব্যবহার উপযোগী করা হয়, কারণ Oil paint-এর Solvent হিসাবে Water মিশ্রিত করা যায় না। Oil paint-কে পাতলা বা নরম করার জন্য Solvent হিসাবে Turpentine ব্যবহার করা হয়।
22254. Quick lime on reacting with water gives- [MOD-20]
hydraulic lime
hydrated lime
poor lime
slaked lime
ব্যাখ্যা: When quick lime is added to water, it reacts to jomm calcium hydroxide (slaked lime). CaO(s) + H2O(l) → Ca(OH)2 (aq) + heat Quick lime Slake lime
22255. Gypsum is added in the manufacture of Portland cement in order to- [MOD-20]
shorten the setting time of cement
lengthen the setting time of cement
decrease the burning temperature
decrease the grinding time
ব্যাখ্যা: Gypsum plays a very important role in controlling the rate of hardening of the cement. During the cement manufacturing process, upon the cooling of clinker, a small amount of gypsum is introduced during the final grinding process. Gypsum is added to control the "setting of cement".
22256. Granite is an example of- [MES-18, MOD-20]
aqueous rocks
sedimentary rock
metamorphic rocks
igneous rocks
ব্যাখ্যা: The rocks in which clay content is predominant are called argillaccous rock. (আগ্নেয় শিলা) The rocks are soft in nature and with the presence of water they can be crumbled easily some of the argillaceous rocks are shale, slate, kaolin, literate etc.
22257. Efflorescence is caused if-. [MOD-20]
the alkaline salt is present in the bricks
the clay used for making bricks contain pyrite
the water used for pugging the clay contain gypsum
all of the above
ব্যাখ্যা: Three factors must be present wherever efflorescence appears: A soluble salt: A variety of salts and salt-forming chemicals can be present in masonry. Water: Moisture is the vehicle that carries the salt 10 the surface of the masonry. Channels: Concrete and bricks have microscopic pores. These tiny channels allow water to move by wicking action.
22258. [MOD-20] What is the unit weight of water?
50 Ib/ft²
62.5 Ib/ft²
90.5 Ib/ft^3
100 lb/ft^3
ব্যাখ্যা: The specific weight, also known as the unit weight, is the weight per unit volume of a material. A commonly used value is the specific weight of water on Earth at 4°C, which is 9.807 kN/m² or 62.5 Ibf/ft².
22259. Which of the following cements is suitable for use in massive concrete structures such as large dams? [BB-20]
Ordinary Portland cement
Low heat cement
Rapid hardening cement
Sulphate resisting cement
ব্যাখ্যা: Low heat cement is one of the hydraulic binding materials and would always be perferred for massive structures such as dams. It has excellent performance such as high final strength, long lasting properties.
22260. French polish is- [PPA-20]
Oil paint
Distemper
Spirit varnish
Asphalt
ব্যাখ্যা: Oil paint is a type of slowdrying paint that consists of particles of pigment suspended in a drying oil, commonly linseed oil.