Answer / sirin dutta chowdhury

This question seems to be wrong.

As temperature increases, resistivity of metals
also increases.These metals are called Ohmic conductors.
The substances, for which conductivity increases with temp
rise dont obey ohm's law and are caller non ohmic
conductors (carbon etc).
The metarials used for transmission lines are all
obviously Ohmic conductors(Cu, Al etc).Hence there is no
question of increse of conductivity of transmission wires
with temp rise.

Adding to it, for this reason, to keep temp rise
within permissible limit,losses of transmission lines are
kept within limit by raising voltage level & reducing
current level through it.

Why material of brush is carbon in motors why not other material.

5 Answers   NTPC,

---

How can we estimate Gen rotor current?

3 Answers  

---

What is the need for checking knee point voltage for CT's?

1 Answers  

---

What is Surge Capacitor? Why it is use in Generator Circuit Breaker?

0 Answers   TCS,

---

What is difference between metal clad & metal enclosed switchgear?

2 Answers  

---

why HT armoured cable does not glanding

0 Answers   TCE,

---

What is the Full form of Rccb,MCCB,

11 Answers   Marriott, Maruti Suzuki, MCB, PCC, RCCB, Torrent Pharma,

---

could you measure current in parallel?

0 Answers  

---

why occ characteristics curve in not tracing back when we are bringing back the rhoestat?

0 Answers  

---

tan delta test of current transformer.

3 Answers   NTPC,

---

What shall be the minimum distance to be maintained between two power cable in a common trench?

3 Answers  

---

if u give d.c. supply to transformer primary then what happen.&why??????????????

4 Answers   DCS, DRDO, HCL,

---