Two underground cables having conductor resistances of 0.7 Ω and 0.5

1.	Two underground cables having conductor resistances of 0.7 Ω and 0.5 and insulation resistance of 300 M Ω respectively are joind (i) in series (ii) in parallel. Find the resultant conductor and insulation resistance.
Answer» (i) The conductor resistance will add like resistances in series. However, the leakage resistances will decrease and would be given by the reciprocal relation. Total conductor resistance = 0.7 + 0.5 = 1.2 Ω If R is the combined leakage resistance, then 1/R = 1/300 + 1/600 ∴ R = 200MΩ (ii) In this case, conductor resistance is = 0.7 × 0.5/(0.7 + 0.5) = 0.3. Ω (approx) Insulation resistance = 300 + 600 = 900 M Ω

Two underground cables having conductor resistances of 0.7 Ω and 0.5 and insulation resistance of 300 M Ω respectively are joind (i) in series (ii) in parallel. Find the resultant conductor and insulation resistance.

Answer»

(i) The conductor resistance will add like resistances in series. However, the leakage resistances will decrease and would be given by the reciprocal relation.

Total conductor resistance = 0.7 + 0.5 = 1.2 Ω

If R is the combined leakage resistance, then

1/R = 1/300 + 1/600

∴ R = 200MΩ

(ii) In this case, conductor resistance is

= 0.7 × 0.5/(0.7 + 0.5) = 0.3. Ω (approx)

Insulation resistance = 300 + 600 = 900 M Ω

Discussion

No Comment Found

Related InterviewSolutions

A multiple plate capacitor has 10 plates, each of area 10 square cm and separation between 2 plates is 1 mm with air as dielectric. Determine the energy stored when voltage of 100 volts is applied across the capacitor.
Three capacitors of 2 μ F, 5 μ F and 10 μ F have breakdown voltage of 200 V, 500 V and 100 V respectively. The capacitors are connected in series and the applied direct voltage to the circuit is gradually increased. Which capacitor will breakdown first ? Determine the total applied voltage and total energy stored at the point of breakdown.
Device used to store energy in electrical circuits is A. resistor B. inductor C. capacitor D. diode
The voltage across a 5microF capacitor change uniformly from 10 to 70V in 5ms. Calculate the change in capacitor charge and charging current.
A resistance R and a 4 μF capacitor are connected in series across a 200 V. d.c. supply. Across the capacitor is a neon lamp that strikes (glows) at 120 V. Calculate the value of R to make the lamp strike (glow) 5 seconds after the switch has been closed.
A parallel-plate capacitor is made of plates 1 m square and has a separation of 1 mm. The space between the plates is filled with dielectric of εr = 25.0. If 1 k V potential difference is applied to the plates, find the force squeezing the plates together
Work done in charging a capacitor is given by A. (1⁄2)QV B. 2QV C. QV D. 2V
Energy stored in a 2000 mF capacitor charged to a potential difference of 10 V is A. 0.12 J B. 1.3 J C. 0.10 J D. 3 J
Capacitor is fully charged if potential difference is equal to A. e.m.f B. current C. resistance D. power
Total capacitance of 300 mF capacitor and a 600 mF in series isA. 300 mF B. 500 mF C. 200 mF D. 1000 mF

Two underground cables having conductor resistances of 0.7 Ω and 0.5 and insulation resistance of 300 M Ω respectively are joind (i) in series (ii) in parallel. Find the resultant conductor and insulation resistance.

Discussion

No Comment Found

Related InterviewSolutions

Reply to Comment