A metal strain gauge has gauge factor of two, it's nominal resistance is $$120$$ Ohms. It is undergoes a strain of $${10^{ - 5}},$$ the value of change of resistance in response to the strain is

A $$220/440$$ $$V,$$ $$50$$ $$Hz$$ single phase transformer operates on $$220$$ $$V,$$ $$40$$ $$Hz$$ supply with secondary winding. Then

A cumulative compounded long shunt motor is driving a load at rated torque and rated speed. If the series field is shunted by a resistance equal to the resistance of the series field, keeping the torque constant.

A synchronous motor operates at $$0.8$$ $$p.f.$$ lagging. If the field current of the motor is continuously increased

$$(1)$$ the power factor decreases upto a certain value of field current and thereafter it increases
$$(2)$$ the armature current increases upto a certain value of field current and thereafter it decreases
$$(3)$$ the power factor increases upto a certain value of field current and thereafter it decreases
$$(4)$$ the armature current decreases upto a certain value of field current and thereafter it increases. From these the correct one is