Define glass. Give its two characteristics.

1 Answer

Answer :

“Glass is amorphous material which is a mixture of silicates, phosphates, borates and other material with 50-80-% silica”.

Characteristics:

1) Glass is most widely used as an insulator.

2) Glass is low in cost.

3) Glasses are having low temperature coefficient.

4) Glasses are having high electric constant.

5) Pyrex glass is most chemically stable and having excellent electrical properties.

Related questions

Description : Define adhesive. Write two characteristics of Adhesive.

Last Answer : Adhesives- Any substance which is capable of holding the materials together by surface attachment is called as an adhesive Characteristics:-  i) Adhesive should form rigid, strong and durable bond. ii ... the adhesion property on storage. v) It should be resistant to heat, chemicals and water.  

Description : Define paint. Give its two properties

Last Answer : Paint: - Paint is a mechanical dispersion mixture of one or more pigment in a vehicle. Properties of paint: 1) Paint imparts opacity and colour to the surface on which it is applied. 2) It ... and weather. 4) Paint imparts luster, gloss and durability to the surface on which it is applied.

Description : Define photo conductive polymer. Give its examples and applications.

Last Answer : Photo conductive polymer: These are the polymers which conduct electricity only in the presence of light. Examples: i) PVK or poly(N-vinyl carbazole ) ii) Poly (vinylpyrene),iii) poly(2- ... resistors are often used include camera light meters, street lights, clock radios and infrared detectors.  

Description : Write two characteristics and two uses of Ni-Cd battery.

Last Answer : Characteristics: 1. The e.m.f. of cell is 1.4 V when fully charged. 2. It has low internal resistance & longer life span (5 years). 3. It is expensive in cost. 4. It can be ... lighting and air conditioning because of its long life & low maintenance cost. 3. It is widely used in calculators.

Description : Define fuel cell. Give the advantages and limitations of H2-O2 fuel cell.

Last Answer : Fuel cell: Fuel cell is an electrochemical cell which converts the chemical energy of fuel directly into the electrical energy by an electrochemical process, in which the fuel is oxidized at the anode. OR ... requires 30% of the stored energy. 7. Life span of the cells is not accurately known.

Description : Write four characteristics of good paint.

Last Answer : i) It should be able to resist the atmospheric conditions. ii) It should have desired consistency. iii) It should have high hiding power. iv) Its film should be washable. v) Its film ... adherent, durable and glossy film.  vii) When paint is applied on a metal, it should resist corrosion.

Description : Define specific conductance. Write its unit.

Last Answer : Specific conductance is the conductance offered by 1 cm3 of the substance or 1ml solution.  OR The conductance offered by a solution or a conducting material having unit length & unit area of cross ... conductance. Unit of specific conductance: ohm-1 cm-1 or mhos-cm-1 or S.cm-1

Description : Define the term equivalent conductance. Write its unit

Last Answer : Equivalent conductance (λv): It is the conductance of the solution containing 1 gm equivalent of solute / electrolyte when placed between two sufficiently large electrodes 1 cm apart. Unit: ohm-1 cm2 / equivalent OR mhos.cm2 /equivalent 

Description : Define charging, discharging, specific resistance and Ohm’s law.

Last Answer : Charging:- It is the operation of the cell in which external source of current reverses the electrochemical cell reaction in order to restore the battery to its original fully charged state. ... across the conductor & inversely proportional to the resistance (R) of a conductor. 

Description : Define extrinsic polymers with example.

Last Answer : Extrinsic polymer- The electrical conductivity of polymers can be increased by doping with a charge transfer agent or by making their composites with other conducting materials like ... called as extrinsic polymer  Examples-Trans-polyacetylene, polyparaphenylene, polypyrrole, polyaniline etc. 

Description : Define the term metallurgy. Name the process of extraction of Aluminium. 

Last Answer : Metallurgy:-The process of extraction of metal from its ore economically & profitably is called as metallurgy. The process used for extraction of Aluminium metal is Bayer’s process, Electrolytic reduction of alumina, Electrolytic refining. 

Description : Define immersed corrosion.

Last Answer : Definition: The corrosion which is brought about through ionic reactions in the presence of moisture or solution as a conducting medium when two dissimilar metals are in contact with each other is called electro chemical corrosion. 

Description : Define liquid crystal polymers.

Last Answer : Liquid crystal polymers are a class of aromatic polyester polymers which are capable of forming regions of highly ordered structure (like crystal) even in the liquid phase.

Description : Define electrochemical corrosion.

Last Answer : Electrochemical corrosion:- The corrosion which is brought about through ionic reactions in the presence of moisture or solution as a conducting medium when two dissimilar metals are in contact with each other is called electro chemical corrosion. 

Description : Define the following: Electrolyte, conductivity of electrolytes, specific conductance and equivalent conductance.

Last Answer : Electrolyte: A substance which produces ions in solution or in fused state and allows the electric current to pass through it, is known as electrolyte. Conductivity of electrolytes: The power ... equivalent of solute / electrolyte when placed between two sufficiently large electrodes 1 cm apart.

Description : Define cementation. Describe sherardizing with help of neat labeled diagram

Last Answer : Cementation: Cementation is the process in which metal coatings are obtained by heating the base metal in a revolving drum containing a powder of the coating metal.   Process: i) The iron articles ... iron forming Fe - Zn alloy at the surface which protects iron surface from corrosion.   

Description : Define Atmospheric corrosion. State the factors affecting rate of atmospheric corrosion. 

Last Answer : Atmospheric corrosion: This type of corrosion occurs when metal surface comes in immediate contact directly with atmospheric gases like O2, Cl2, Br2, I2, H2S, CO2, SO2, NO2 etc.  Factors affecting rate of atmospheric corrosion:- 1) Impurities in the atmosphere. 2) Moisture in the atmosphere. 

Description : Define atmospheric corrosion. Write mechanism of atmospheric corrosion with diagram.

Last Answer : Atmospheric corrosion: This type of corrosion occurs when metal surface comes in immediate contact directly with atmospheric gases like O2, Cl2, Br2, I2, H2S, CO2, SO2, NO2 etc.

Description : Define the terms: i) Photo conductive polymers ii) Liquid crystal polymers 

Last Answer : i) Photo conductive polymers: These are the polymers which conduct electricity only in the presence of light.  ii) Liquid crystal polymers: These are a class of aromatic polyester polymers. These polymers have tendency to align their chains parallel over a long distance from their melt or solution.

Description : Define the terms : i) Specific conductance ii) Equivalent conductance

Last Answer : i) Specific conductance (k) : Specific conductance is the conductance of a 1 cm3 of the substance or solution.  OR The conductance offered by a solution of length 1 cm & ... containing 1gm equivalent of solute / electrolyte when placed between two sufficiently large electrodes 1 cm apart.

Description : Give the composition of rose metal and its one application.

Last Answer : Composition: Bi = 50%  Pb = 28%  Sn = 22% Applications:- 1.It is used for making fire alarms. 2.It is used in electrical fuse wires. 3.It is used for casting for dental works. 4.It is used in automatic sprinkler system.

Description : Name two types of adhesives and give their uses. 

Last Answer : Sr. No. Types of adhesives Uses of adhesives  1 Thermosetting synthetic resins It is used for making water-proof plywoods, laminates, bonding articles in aircraft and ship building ... 7 Animal glues In manufacturing furniture, radio-cabinates and card-boxes etc.

Description : Classify electrochemical cells. Give examples of each.

Last Answer : Electrochemical cells are classified as: 1) Primary cells. 2) Secondary cells. Examples of primary cells: Dry Cell (Leclanche’s cell). Daniel Cell. Examples of secondary cells: Lead-acid storage cell. Ni-Cd battery.

Description : Explain cathodic protection. Give one example.

Last Answer : Cathodic protection: It is the method in which the metal to be protected is forced to behave as a cathode. Examples: 1) To protect buried water or gas pipelines. 2) To protect buried cables. 3) ... water box coolers. 6) To protect water tanks. 7) To protect transmission line towers, etc.  

Description : Give the applications of phenol formaldehyde resin.

Last Answer : 1) For making electric insulator parts like switches, plugs, switchboards, heater-hands, sockets for light bulb, etc. and in wire insulation. 2) Used for making moulded articles like telephone parts, ... ) In paints and varnishes. 7) It is used as hydrogen- exchanger resin in water softening.

Description : Give any four application of electrically conducting polymers

Last Answer : 1 They are used in rechargeable batteries 2 They are used as analytical sensors to detect pH, O2 ,NO2, SO2, NH3, glucose etc 3. They are used as antistatic materials in offices, theatres ... wall papers, light emitting diodes &data storage. 7. They are used in construction of photo voltaic cell

Description : Galvanized containers are not used for storage of food. Give reason.

Last Answer : Galvanized containers (zinc coated) cannot be used for preparing and storing food stuff, which are acidic in nature because zinc gets dissolved in dilute acids in food forming poisonous zinc compounds which will poison the content.

Description : Describe metal spraying process for protection of metal from corrosion .Write its two applications.

Last Answer : Process:- i) In this method, coating metal sprayed on the surface of base metal with the help of spraying gun or pistol. ii) The spraying gun consist of a duct for compressed air and is fitted with the oxy- ... 4) Coating of metals like Al, Zn, Ni, Sn, Pb etc. is made by the method of spraying.

Description : Describe the tinning process. Write its two applications.

Last Answer : Tinning: -The process of covering iron or steel sheets with a thin coat of tin to prevent it from rusting is called as tinning.   Process: i) The sheet of steel to be ... Tinned copper sheets are used for cooking utensils and refrigeration equipment. Cu tubes are used in refrigeration. 

Description : Name the sequential steps involved in extraction of copper from its copper pyrite ore.

Last Answer : sequential steps involved in extraction of copper from its copper pyrite ore

Description : Write two properties and two uses of Bakelite.

Last Answer : Properties Uses Hard,Rigid,strong,scratch resistant & brittle material. insulation of electrical wires & cables electrical switches, switch board sockets, plugs for ... Rolling mills, Decorative laminates wall covering & industrial laminates for electrical parts. 

Description : State the two methods of Hot dipping. 

Last Answer : Two methods of hot dipping-1. Galvanizing 2. Tinning

Description : State the two functions of pigment.

Last Answer : 1) Provide opacity and colour to paint film. 2) Give strength to the film. 3) Give protection to the paint film by reflecting harmful ultraviolet light. 4) Provide resistance to paint film against abrasion, ... and weather. 5) Give an aesthetical appeal (i.e pleasing to look at) to the paint film.

Description : State two properties and two uses of silicone fluids.

Last Answer : Properties :- 1. They can be used in temperature range of -90 0C to 220 0C 2. They have excellent dielectric properties over a wide range of temperature 3. They have ... release material: an odourless, non-toxic, noncarbonizing moulds release for rubber, plastics and metal die castings.

Description : State two applications of lead acid storage cell.

Last Answer : Applications of lead acid storage cell: 1. Lead acid storage cellis commonly used in automobiles. 2. To Supply current for electric vehicles 3. In Gas engine ignition 4. In telephone exchanges ... hospitals 7. In broad casting stations, power stations 8. For distribution work 9. In inverters

Description : Write two applications and two properties of Rose metal.

Last Answer : Properties: 1. It is easily fusible alloy. 2. It’s melting point is 89 0C. Applications: 1. It is used for making fire – alarms, fuses wires. 2. It is used for casting dental works 3. It is used in automatic sprinkler system.

Description : Write two applications of copper.

Last Answer : 1) For making electrical wires, cables and conducting apparatus. 2) As a coinage metal and in ornaments, jewelry for making them hard. 3) For making water stills, kettles, vacuum pans, steam pipes ... such as hypsometers, colorimeters, etc. 7) For making alloys like brass, bronze, gun metal, etc.

Description : Explain fuel cell. State two advantages.

Last Answer : Fuel cell- Fuel cell is a electrochemical cell which converts the chemical energy of fuels directly into electrical energy by an electrochemical process in which the fuel is oxidized at the ... fossil fuels 15. Fuel cell automotive batteries can render electric vehicles efficient & refillable  

Description : Write any two applications of silicon fluid. 

Last Answer : Applications:- 1) As a lubricant: excellent lubrication for plastic and elastomeric surfaces. 2)In polishes and chemical specialities: It is used in automobile and furniture polishes due to its high ... ,non-toxic , non-carbonizing moulds release for rubber, plastics and metal die castings. 

Description : Write any two examples of sacrificial anodic protection.

Last Answer : Examples: 1) To protect buried water or gas pipelines. 2) To protect buried cables. 3) To protect hot water tank, etc. 4) Mg or Zn rods are bolted along the sides of ship, hot water ... protect open water box coolers. 6) To protect water tanks. 7) To protect transmission line towers, etc. 

Description : Write any two advantages of Adhesives.

Last Answer : i) Adhesives have an advantage of joining material such as glass & metal, metal metal, metal & plastic, plastics-plastic, ceramic & ceramic. ii) Surfaces are easily & rapidly attached to each ... are leak proof for gases & liquids. So adhesive bonding is used in preparing water tight wood boats

Description : Name any two constituents of paints with two functions of each.

Last Answer : Constituents of paint: 1. Pigments 2. Vehicle or medium (drying oil) 3. Thinners 4. Driers 5. Fillers 6. Plasticizers Functions of various constituents: Pigments: i) Provides opacity and desired ... i) To give elasticity to the paint film. ii) To prevent the cracking of the film.

Description : Write two application of metal cladding process.

Last Answer : Applications : 1) Al clad sheets used in aircraft industry in which a plate of duralumin is sandwiched between two layers of 99.5% pure Al. 2) Cu clad steel wire is obtained by ... cu-tube is used for electrical conductors possessing combining strength of steel with the high conductivity of Cu.

Description : Name two ores of Aluminum with chemical formulae.

Last Answer : Ores of Aluminum:(Any two) i) Bauxite - Al2O3 .2H2O. ii) Corundum- Al2O3, iii) Feldspar - KAlSi3O8, iv) Mica - [KAlSi2O10(OH)2] v) Cryolite - Na3AlF6 vi) Alunite ( Alumstone)- K2SO4 .Al2(SO4)3 .4Al(OH)3

Description : Write two applications of Teflon

Last Answer : Applications of Teflon: i) Teflon used as capacitor dielectrics & insulating material for all kinds of windings. ii) Heat resistant materials are prepared by combining Teflon with glass cloth. iii ... . vii) Teflon coating is applied on vehicle to protect them from corrosion and scratches. 

Description : Write two points of similarity between sherardizing and galvanising process.

Last Answer : 1) Sherardizing and galvanizing are the processes of avoiding corrosion of metal. 2) Zinc is used as coating metal on iron base metal.

Description : Write two applications of aluminum

Last Answer : 1) For preparing utensils, surgical instruments, heating appliances, parts of aeroplanes, containers for chemical industry etc. 2) For making electric wires and cables for transmission lines. 3) ... storing nitric acid. 13) As refractory for lining of furnace and for making refractory bricks.

Description : Write the action of Nitric acid on Aluminium.

Last Answer : Aluminium metal does not react with dilute as well as concentrated Nitric acid 

Description : What are applications of sherardizing process?

Last Answer : Applications:- i)Sherardizing is used especially for protecting small odd shaped steel articles like bolts, screws, nuts, threaded parts washers, valves, gauge, tools etc.against atmospheric corrosion. ... has crevices or depression and there is practically no change in the dimensions of articles.

Description : Explain discharging and charging process of lead acid storage cell. 

Last Answer : Discharging: - While discharging chemical energy gets converted into electrical energy. At anode: - The lead electrode loses electrons, which flow through the wire.   Lead sulphate is precipited at ... are reversed by passing an external e.m.f. greater than 2 volts from a generator.