Instrument transformers are known to introduce magnitude and phase errors in measurements. These are primarily due to

A potentiometer is basically

A transfer instrument employed in the standardization of a polar type $$a.c$$ potentiometer is ______

The primary current in a current transformer is dictated by

In $$d.c.$$ potentiometer measurements, a second reading is often taken after reversing the polarities of the $$s.c.$$ supply and the unknown voltage, and the average of the two readings is taken. This is, with a view to eliminate the effects of

A $$200/1$$ current transformer $$(CT)$$ is wound with $$200$$ turns on the secondary on a toroidal core. When it carries a current of $$160$$ $$A$$ on the primary, the ratio and phase errors of the $$CT$$ are found to be $$-$$ $$50$$% and $$30$$ minutes respectively. If the number of secondary turns is reduced by $$1$$ the new ratio error (%) and phase error (min) will be respectively.

A $$50$$ $$Hz,$$ bar primary $$CT$$ has a secondary with $$500$$ turns. The secondary supplies $$5A$$ current into a purely resistive burden of $$1\,\Omega $$. The magnetizing ampere-turns is $$200$$. The phase angle between the primary and secondary current is

The core flux in the $$CT$$ of above problem under the given operating condition is

A $$500$$ $$A/5$$ $$A,$$ $$50$$ $$Hz$$ current transformer has a bar primary. The secondary burden is a pure resistance of $$1\,\Omega $$ and it draws a current of $$5A$$. If the magnetic core requires $$250$$ AT for magnetization, the percentage ratio error is

A d.c. potentiometer is designed to measure up to about $$2$$ $$V$$ with a slide wire of $$800$$ mm. A standard cell of emf $$1.18V$$ obtains balance at $$600$$ mm. A test cell is seen to obtain balance at $$680$$ mm. The emf of the test cell is