The electrical resistivities of four materials P,Q,R and S are given below:
`{:(P,,6.84 xx 10^(-8) Omegam),(Q,,1.70 xx 10^(-8) Omega m),(R,,1.0 xx 10^(15) Omega m),(S,,11.0 xx 10^(-7)Omega m):}`
Which material will you use for making: (a) heating element of electric iron (b) connecting wire of electric iron (c) covering of connecting wires? Give reason for your choice in each case.

The electrical resistivities of four materials A,B,C and D are given below: {:(A,,110 xx 10^(-8)Omegam),(B,,1.0 xx 10^(10) Omega m),(C,, 10.0 xx 10^(-8)Omega m),(D,,2.3xx 10^(3) Omega m):} Which material is: (a) good conductor (b) resistor (c) insulator, and (d) semiconductor?

The electrical resistivities of three materials P,Q and R are given below: {:(P,,2.3 xx 10^(3)Omega m),(Q,,2.63 xx 10^(-8)Omegam),(R,,1.0 xx 10^(15)Omega m):} Which material will you use for making (a) electric wires (b) handle for soldering iron, and (c) solar cells ? Give reasons for your choices.

The electrical resistivities of five substances A,B,C,D and E are given below: {:(A,,5.20 xx 10^(-8)Omega m),(B,,110 xx 10^(-8) Omega m),(C,, 2.60 xx 10^(-8) Omega m),(D,,10.0 xx 10^(-8) Omega m),(E,,1.70 xx 10^(-8) Omega m):} (a) Which substance is the best conductor of electricity? why? (b) Which one is a better conductor: A or C? Why? (c) Which substance would you advise to be used for making heating elements of electric irons? Why? (d) Which two substances should be used for making electric wires? Why?

The specific conductance in ohm- cm- of four electrolytes P, Q, R and S are given in brackets: {:(P(5.0 xx 10^(-5)),Q(7.0 xx 10^(-8))) ,(R(1.0 xx 10^(-10)),S(9.2xx 10^(-3))) :} The one that offer s highest resistance to the passage of electric current is:

(a) What is meant by saying that the potential difference two points is 1 volt ? Name a device that helps to measure the potential difference across a conductor. (b) Why does the connecting cord of an electric heater not glow hot while the heating element does ? ( c) Electrical resistivities of some substances at 20^@ C are given below : Silver 1.60 xx 10^-8 Omega m Copper 1.62 xx 10^-8 Omega m Tungsten 5.20 xx 10^-8 Omega m Iron 10.0 xx 10^-8 Omega m Mercury 94.0 xx 10^-8 Omega m Nichrome 100 xx 10^-6 Omega m . Answer the following question in relation to them : (i) Among silver and copper, which one is a better conductor ? Why ? (ii) Which material would you advise to be used in electrical heating devices ? Why ?

The resistivity of three metals namely iron, silver and mercury are 10xx10^(-8) Omegam, 1.6xx10^(-8) Omega and 94xx10^(-8) Omega m respectively. Answer the following using given data (a) Which among iron, silver and mercury is the best conductor ? (b) If the length of the iron conductor is doubled, what will happen to its resistivity ? Given reason for your answers.

The conductivity of four electrolytes P, Q, R, S in ohm^(-1) cm^(-1) area as follows P (5 xx 10^(-6)), Q (1 xx 10^(-10)), R (7 xx 10^(-8)), S(9.2 xx 10^(-3)) . The one which offers highest resistance to the passage of electric current is

The electricity resistivity of a few materials is given in ohm-metre. Which of these materials can be used for making element of a heating device ? {:(A,6.84xx10^(-8)),(B,1.60xx10^(-8)),(C,1.00xx10^(-4)),(D,2.50xx10^(12)),(E,4.40xx10^(-5)),(F,2.30xx10^(17)):} Give reason for your answer.

The electrical resistivities of a few materials are given in ohm.metre. Which of these materials can be used for making an element of a heating device ? (A) 6.84 xx 10^-8 (B) 1.60 xx 10^-8 ( C) 1.00 xx 10^-4 (D) 2.50 xx 10^12 ( E) 4.40 xx 10^-5 (F) 2.30 xx 10^17 .