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261.

Total load transmitted through a 3-phase transmission line is 10,000 kW at 0.8 power factor lagging. The I2 R losses are 900 kW. The efficiency of transmission line is

A.	60%	B.	90%
C.	95%	D.	99%

262.

Litz wire, is used for intermediate frequencies to overcome

A.	corona effect	B.	skin effect
C.	radio interference	D.	All of the above

263.

In order to reduce skin effect at UHF

A.	conductors are painted	B.	conductors are anodised
C.	copper tubes with silver plating are used	D.	copper rods with silver plating are used

264.

The chances of corona are maximum during

A.	summer heat	B.	winter
C.	dry water	D.	humid weather

265.

Neglecting losses in a transmission system, if the voltage is doubled for the same power transmission, the weight of conductor material required will be

A.	four times	B.	double
C.	half	D.	one-fourth

266.

In case the characteristic impedance of the line is equal to the load impedance

A.	all the energy will pass to the earth	B.	all the energy will be lost in transmission losses
C.	the system will resonatc badly	D.	all the energy sent will be absorbed by the load

267.

Which type of insulators are used on 132 kV transmission lines?

A.	Pin type	B.	Disc type
C.	Shackle type	D.	Pin and shackle type

268.

Which distribution system is more reliable?

A.	Ring main system	B.	Tree system
C.	Radial system	D.	All are equally reliable

269.

Out of the following system of distribution, which system offers the best economy?

A.	Direct current system	B.	AC single phase system
C.	AC 3 phase 3 wire system	D.	AC 3 phase 4 wire system

270.

The advantage of dc transmission system over ac transmission system is

A.	dc system it economical	B.	there is no skin effect in dc system
C.	corona limits are highest for dc circuits as compared to ac circuits	D.	All of the above