Already have an account? Get multiple benefits of using own account!
Login in your account..!
Remember me
Don't have an account? Create your account in less than a minutes,
Forgot password? how can I recover my password now!
Enter right registered email to receive password!
Explain why nichrome and not copper is used as heating element whereas manganin is used as standard resistance?
For heating elements, primary requirements are high melting point, high electrical resistance and low thermal expansion. Last two requirements help in reducing thermal fatique because of repeated heating and cooling. Heating elements must be designed in a way as to allow unhindered expansion and contractions for instance, in the form of a coil of wire. Nichrome (80% nickel & 20% chromium) has all above, mentioned requirements and can be used up to 1300°C. So, nichrome and not copper is used as heating element. Additionally melting point of copper is 1083°C, which is less than nichrome.
For resistor applications, primary requirements are uniform resistivity, small temperature coefficient of resistance, stable resistance and low thermo electric potential with respect to copper. A small α minimizes erron in measurement because of variations in ambient temperature. α is defined as α = 1/R= dR/dT where R is resistance of the alloy at temperature T. For Manganin alloy (87% copper and 13% manganese) α is only 20 x 10-6/K as against 4000x10-5/K for pure copper. Therefore manganin is used as standard resistance.
On the basis of application, how are dyes classified? Describe essential features of any two of them.
Calculate the activity co-efficient? The solubility of gaseous O 2 at a partial pressure of 1.01 bar and a temperature of 310.2K, ex- pressed as a concentration, is 1.07 *10 -
Ammonia is oxidised with air to form nitric oxide in the first step to produce nitric acid. The reaction occurs in a well insulated continuous reactor based on the stoichiometry:
Saturated and unsaturated compounds If, in an organic compound consisting of two or more carbon atoms, there are just only single bonds among carbon atoms, after that the comp
hitorff method
Explain the Purposes of tempering Tempering is a heat treatment approach for alloys and metals. In steels, tempering is done to "toughen" the metal by transforming brittle ma
Classify each reaction and give the name of all the chemical formula involved for each number. 1. Na2CO3(s) + SiO2(s) ? Na2SiO3(l) + CO2(g) 2. 2 Mg(NO3)2(s) ? 2 Mg(NO2)2(s) + O2
which kind Acid &Basic radical present in this?
NaOH + K2Cr2O7 ---> HCo + NaHCO3 ---> HCo + NaOH ---> CuSo4 + NaOH ---> CH3COOH + NaHCO3 ---> PbNO3 + KI --->
Pre And Primary Processing -Some Basic Concepts In the earlier three units, we learnt about the principles and methods of food processing. Certain issues related to production,
Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!
whatsapp: +1-415-670-9521
Phone: +1-415-670-9521
Email: [email protected]
All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd