2021 EE

As a loop ot wire with a resistance of 10 ohm moves in a constant non-iniform magnetic field, it Loses kinetic energy at a uniform ra 4 mJ/s: Determine the induced current in the 1cop.

• 10 mA

• 30 mA

• 20 mA

• cannot be calculated from the given data

A piece of conductor 10 cm long moves across the magnetic field of: 10 k gauss at a velocity of 120 cm/s. What is the voltage across the conductor?

• A. 12 mV

• B. 1.20 mV

• C. 120 mV

• D. 0.12 mV

One primary and one secondary terminal of a two-winding transformer is connected to an ohm-meter instrument. What will be the reading on this instrument?

• A. impedance is doubled

• B. zero

• C) infinity

• D. equal to winding resistance

A car battery is rated at 80 ampere-hour. An ampere-four is a unit of ____

• A. power

• B: energy

• C. charge

• D. current

The boundary of the protection system is determined by the location of

• A. voltage transformers

• B. current transformers

• C. Protective realys

• D. circuit breakers

GMC was created by the Energy Regulatory Commission to monitor the compliance of the users of the Grid to the PGC. What is the GMC stands for?

• A. Grid Market Commission

• B. Generation Management Corporation

• C. Grid Management Committee

• D. Generator Management Committee

Increasing the voltage of the transmission system to double of its original value with the same power to be transmitted, the new power losses of the transmission system will be of the original value.

• A. twice

• B. one half

• C. the same

• D. one-fourth

Calculate the value of aj+1.

• A. 0.5 + j 0.866

• B. 1 + j 0

• C. 0.866 - j 0.5

• D. 0.134 - j 0.5

The line currents in a three-phase, four-wire system are Ia = 30 ÷ j 40, Ib = 20 + j 20 and Ic = -40 - j 20 S, respectively. What is the negative sequence current for phase A in Ampere?

• A. -25 + j 4

• B. 25 - j 4

• C. 25 - j 4

• D. -25 - j 4

The resistance of the primary coil of a well-designed 1:10. step-down transformer is 1 ö. With the secondary circuit open, the primary is connected to a 12 V ac generator. What is the primary current?

• A. About 12 A

• B. Depends on the core material

• C. About 120 A

• D. Essentially zero