EE MCQ

SSC JE Electrical 2019 with solution SET-1
######
In the circuit shown, the pressure coils of two wattmeters are connected to

In Two wattmeter method the current coils of the wattmeter are connected with any two lines, say R and Y and the potential coil of each wattmeter is joined across the same line, the third line i.e. B as shown below in the figure . In the circuit B is the common point for both the wattmeter.

Related Question

SSC JE Electrical 2019 with solution SET-1
######
An electric motor in which both the rotor and stator fields rotate with the same speed is called

In the synchronous motor, the stator and rotor rotate at the same speed.

SSC JE Electrical 2019 with solution SET-1
######
A magnetic circuit is applied with a current that changes at a rate of 5 A/sec. The circuit has an inductance of 2H, then the self-induced EMF is

Given

Inductance L = 2 H

Rate of change of current di/dt = 5 A/sec

Self induced EMF = − (Rate of change of current × Inductance) = −L(di/dt)

= −(5 × 2) = −10V

SSC JE Electrical 2019 with solution SET-1
######
The amount of AC content present in the DC output of a rectifier is given by

Ripple factor: The output of the rectifier is of pulsating d.c. type. The amount of a.c. content in the output can be mathematically expressed by a factor called the ripple factor (γ). The ripple factor expresses how much successful the circuit is, in obtaining pure d.c from a.c. input.

Less is the ripple factor, better is the performance of the circuit.

Ripple Factor γ = R.M.S value of a.c component of output ⁄ Average or d.c component of the output