A set of $$3$$ equal resistors, each of value $${R_X},$$ connected in star across $$RYB$$ of given Fig. consumes the same power as the unbalanced delta-connected load shown. The value of $${R_X}$$ is _____________ $$\Omega .$$

A precise measurement guarantees accuracy of the measured quantity.

A $$0$$-$$10$$ $$mA$$ $$PMMC$$ ammeter reads $$4$$ $$mA$$ in a circuit. Its bottom control spring snaps suddenly. The meter will now read nearly

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