$50$ kVA, $6360$ V$/230$ V transformer is tested on open and short$-$circuit to obtain its efficiency, the results of the test are shown in Table $2.$ Find the efficiency of the transformer when supplying full load at a power factor of $0\mathrm{.}8$ lagging.

QUESTION NO$.4(10$ Marks$)$

A $50$kVA,$6360\frac{V}{230}V$ transformer is tested on open and short$-$circuit to obtain its efficiency, the results of the test are shown in Table $2.$ Find the efficiency of the transformer when supplying full load at a power factor of $0\mathrm{.}8$ lagging.

Table $2$

$\backslash$table$[[$Type of Test,$\backslash$table$[[$Primary$],[$Voltage $($V$)]],\backslash$table$[[$Primary$],[$Current $($A$)]],\backslash$table$[[$Secondary$],[$Current $($A$)]],\backslash$table$[[$Power Input$],[(kW)$