Meter constant = No. of revolution/kWh
Hence the number of revolutions made by the disc for 1 kWh of energy consumption is called meter constant.
The meter constant is always written on the name plates of the energy meters installed m homes, commercial and industrial establishments. If the meter constant of an energy meter is 1500 rev/kWh, it means that for the consumption of 1 kWh, the disc will make 1500 revolutions.
The circuit shown in the question is an AND GATE. In an AND gate has two or more inputs but it has only one output. An input signal applied to a gate has only two stable states, either 1 (HIGH) or 0 (LOW). In AND gate for any input A&B the output is A.B.
In the capacitor start, single-phase induction motor the capacitor is connected in series with the starting auxiliary winding. In this manner, the current in the starting winding may be made to lead the line voltage. Since the running winding current lags the line voltage, the phase displacement between the two currents is made to approximately 90° on starting.
Placing the capacitor in the auxiliary winding circuit to produce a greater phase difference between the current in the main and the auxiliary windings. Due to greater phase difference capacitor Start motors have very high starting torque for a single-phase AC motor.
The luminous efficiency of an electric lamp is the ratio of the luminous flux (in lumen) emitted by the lamp to the electric power (watt) given to it i.e.
Luminous efficiency η = Luminous flux/Watt
Note:- Lumens is the unit of measurement for luminous flux, which is the total amount of visible light emitted by a source.
The resistance R3 & R4 are connected in series
= (30 + 70) = 100Ω
Now three resistor i.e 100Ω, 100Ω & 50Ω is connected in parallel
1/Rp = 1/100 + 1/100 + 1/50
Rp = 100/4 = 25 Ω
Resistance 50Ω and 25Ω are connected in series.
Rtotal = (50 + 25)Ω
Rtotal = 75Ω