1
GATE EE 2006
MCQ (Single Correct Answer)
+2
-0.6
A $$300$$ $$kVA$$ transformer has $$95\% $$ efficiency at full load $$0.8$$ $$pf$$ lagging and $$96\% $$ efficiency at half load, unity $$pf.$$

What is the maximum efficiency (in %) at unity $$pf$$ load?

A
$$95.1$$
B
$$96.2$$
C
$$96.4$$
D
$$98.1$$
2
GATE EE 2006
MCQ (Single Correct Answer)
+2
-0.6
A $$300$$ $$kVA$$ transformer has $$95\% $$ efficiency at full load $$0.8$$ $$pf$$ lagging and $$96\% $$ efficiency at half load, unity $$pf.$$

The iron loss $$\left( {{P_i}} \right)$$ in $$kW,$$ under full load operation are

A
$${P_c} = 4.12,\,\,{P_i} = 8.51$$
B
$${P_c} = 6.59,\,\,{P_i} = 9.21$$
C
$${P_c} = 8.51,\,\,{P_i} = 4.12$$
D
$${P_c} = 12.72,\,\,{P_i} = 3.07$$
3
GATE EE 2006
MCQ (Single Correct Answer)
+1
-0.3
In transformers, which of the following statements is valid?
A
In an open circuit test, copper losses are obtained while in short circuit test, core losses are obtained.
B
In an open circuit test, current is drawn at high power factor.
C
In a short circuit test, current is drawn at zero power factor
D
In an open circuit test, current is drawn at low power factor.
4
GATE EE 2006
MCQ (Single Correct Answer)
+1
-0.3
Which of the following statements holds for the divergence of electric and magnetic flux densities?
A
Both are zero
B
These are zero for static densities but non zero for time varying densities
C
It is zero for the electric flux density
D
It is zero for the magnetic flux density