assertion- alloys are commonly used in electrical heating devices like electric iron and heater. reason- resistivity of an alloy is generally higher than that of its constituent metals but the alloys have low melting points than their constituent metals. explain - chemistry q&a
an alloy is combination of a metal and a non metal. so it has partial characteristics of metal and non metal. being analloy the ions it it are randomly arranged. it does not have a specific arrangement of ions. hence the flow of electrons in this is more. the this feature of alloy leads to increase in resistivity due to free crystal lattice. we know that metals have high melting point but an alloy has low melting point beacause the presence of a non metal in it behaves as an impurity and restricts in raising to high melting point. due to high melting point the it takes a lot of current to melt and leads in slow movement of electrons which makes the device less efficient. therefore electronic device requires the metal of low melting point. an alloy plays the best role in the elctronic device like electric iron and heater.
(a) material q with resistivity 2.63×10-8 ohm-m can be used for making electric wires because it has very low resistivity.(b) material r with resistivity 1.0 ×1015 ohm-m can be used for making handle of soldering iron because it has very high resistivity.(c) material p with resistivity 2.3 × 103 ohm-m can be used for making solar cell because it is a semiconductor. of the two different tools, research has shown that electrical conductivity diamond testers are much better than thermal conductivity diamond testers. they are higher in price, but much more accurate. heat testers are much cheaper but their accuracy is not as high, so may not get as good results. electricity-based diamond tester ions are responsible for the conductivity of electricity but in case of covalent compounds there are no free ions. so, covalent compounds are poor conductor of electricity. tagging|||chemistry||metals and non metals||reaction of metals and non metals Answer  
Atoms prefer to have a filled outermost shell because this makes them more stable.  
Atoms react with each other to get the most stable state possible. A filled outermost shell (a  
complete octet for s- and p-elements) is very stable because all orbitals are filled with  
electrons. Stability of an atom is connected with its energy. Atoms with greater stability have  
less energy. We can see this in chemical reactions: a reaction that increases the stability of the  
atoms will release energy in the form of heat or light. as the length of the wire increases so does the electrical resistance as electrons experience a smaller pd gradient as wire gets longer. the size of voltage per metre value decreases causing a lower drift velocity and more ions for electrons to collide with I have used both ABS and PLA for diesel gas caps and oil plugs. As well have made a gasoline funnel out of both. Both have done well for me.  
 I have attach a link to a plastics resistance chart if it is any help. Unfortunately it does not show testing for ABS for all. 

 I prefer the ABS only do to the fact some items I have made sit in the desert sun. 

 [Plastic resistance chart](http://www.plasticsintl.com/plastics_chemical_resistence_chart.html) 1. introduction: rough surface in contact i. surface of engineering materials: generals  surfaces have chemical properties, which are different from bulk virgin material. o most metallic surfaces in air have oxide layers, which change the chemical and mechanical properties of the surfaces.  surfaces have mechanical properties, which are different from bulk material. o machining or sliding contact makes strain hardened (or work hardened) layer and highly deformed layer, whose strength are different from bulk.  real engineering surfaces are rough. mirror like smooth surface afm image The physical and chemical properties of elements depend on the number of valence electrons. Elements present in the same group have the same number of valence electrons. Therefore, elements present in the same group have similar physical and chemical properties. Tungsten, also known as wolfram, is a hard, rare metal that is found naturally only in chemical compounds. The free element is remarkable for its robustness, especially the fact that it has the highest melting point of all the elements.  
Tungsten in pure form has the highest melting point (3422 °C, 6192 °F), lowest vapor pressure (at temperatures above 1650 °C, 3000 °F) and the highest tensile strength. Tungsten has the lowest coefficient of thermal expansion of any pure metal. The low thermal expansion and high melting point and tensile strength of tungsten originate from strong covalent bonds formed between tungsten atoms by the 5d electrons. Alloying small quantities of tungsten with steel greatly increases its toughness. a) he helium (he) is an element by itself. he atom can only exhibit dispersion forces.b) hclh          1a                   1 × 1 e– = 1 e–cl         7a                   1 × 7 e– = 7 e–   total: 8 valence e–[readmore]cl is more electronegative than h, so hcl is a polar covalent compound. hcl exhibits dipole-dipole interaction.c) h2oh          1a                   1 × 2 e– = 2 e–o          6a                   1 × 6 e– = 6 e–   total: 8 valence e– since hydrogen is bonded directly to oxygen.h2o exhibits hydrogen bonding.d) cl2cl         7a                   1 × 7 e– = 14 valence e–composed of the same atom. there's no electronegativity difference.cl2 can only exhibit dispersion forces.