An $$LPF$$ wattmeter of power factor $$0.2$$ is having three voltage settings $$300V,$$ $$150V$$ and $$75V,$$ and two current settings $$5 A$$ and $$10A.$$ The full scale reading is $$150.$$ If the wattmeter is used with $$150V$$ voltage setting and $$10A$$ current setting, the multiplying factor of the wattmeter is __________.

While measuring power of a three-phase balanced load by the two-wattmeter method, the readings are $$100$$ $$W$$ and $$250$$ $$W$$. The power factor of the load is ___________.

Power consumed by a balanced $$3$$-phase, $$3$$-wire load is measured by the two wattmeter method. The first wattmeter reads twice that of the second. Then the load impedance angle in radians is

For the circuit shown in the figure, the voltage and current expressions are
$$v\left( t \right) = {E_1}\sin \left( {\omega t} \right) + {E_3}\sin \left( {3\omega t} \right)$$ and
$$i\left( t \right) = {{\rm I}_1}\sin \left( {\omega t - {\varphi _1}} \right) + {{\rm I}_3}\sin \left( {3\omega t - {\varphi _3}} \right) + {{\rm I}_5}\sin \left( {5\omega t} \right)$$

The average power measured by the Wattmeter is