Test: Ohm’s Law - UPSC MCQ

Materials which obeys the ohm’s law show straight line in the V-I graph. Since silver is the only ohmic material in given options, it shows straight line curve.

The slope of the graph = I / V

In case of T₂, I/V is less. Hence, V/I (=R) is more.

Value of resistance increases with increasing temperature. 

Hence, T₂ >T

I=Q/t
1 Ampere = 1 Coulomb /1 Secon
Charge on 1 electron = 1.6 x 10^-19
Coulomb
By unitary method,
If 1.6 x 10^-19 Coulomb / Second (Ampere) = Current by 1 electron
then, 1( Coulomb / Second) or (Ampere) = 1 / (1.6 x 10^-19) electrons
i.e, 6.25 x 10^18 electrons.

1 Ohm is defined as the resistance of a conductor with a potential difference of 1 volt applied to the ends through which 1-ampere current flows.
Ohms is the SI unit of electrical resistance.
 

Ohmic conductors are those which follows ohm's Law

Constantan is an copper nickle alloy which follows ohm's law 

An electrolyte is a chemical that produces an electrically conducting solution and hence conducts electrical current.

But Electrolyte can be  Ohmic as well as non-ohmic conductor

Transistor is semi-conductor device and does not follow ohm's Law

thermionic valves  - is vacuum tube (electronic tube) , uses ion emission.

So option C Constanton s an ohmic conductor.