EECOACH 1

Which of the following type of fault used only the equivalent positive and negative sequence impedance of the circuit in the short-circuit calculation?

• Line to line

• Line to ground

• Three-phase

• Double line to ground

The terminal voltage of a battery is 11.8 V when delivering 20 W of power to an external load resistor R. If the battery has an emf of 15 V, find the internal resistance of the battery.

• 1.96 ohm

• 1.75 ohm

• 1.89 ohm

   

• 1.68 ohm

A capacitor in an LC oscillator has a maximum potential difference of 15V and a maximum energy of 360uJ. At a certain instant the energy in the capacitor is 40uJ. At that instant what is the potential difference across the capacitor?

• 15 V

• 10 V

• 5 V

   

• 25 V

The current is zero in a conductor when NO potential difference is applied because

• the electrons are not moving fast enough

   

• for every electron with a given velocity there is another with a velocity of equal magnitude and opposite direction

• equal numbers of electrons and protons are moving together

• the electrons are not moving

In a series circuit, the current is

• constant

   

• inversely proportional to the resistance

• proportional to the resistance

• variable

RA 7832 concerns on

• pilferage of electricity and electrical materials

   

• pilferage of electrical energy

• pilferage of electricity, theft of transmission materials and rationalizing of system loss

• pilferage of electricity, theft of transmission materials and capping of system loss

What is the purpose of reactor in short circuit?

• To open the line in short circuit

   

• To increase the current in short circuit

• To lessen the current in short circuit

• To decrease the circuit resistance

The magnetic field B inside a long ideal solenoid is independent of:

• the cross-sectional area of the solenoid

   

• the current

• the core material

The power factor of incandescent bulb is

• 0.8 leading

• 0.8 lagging

• zero

• unity

The power transmission capacity of the transmission is

• proportional to the cube of the voltage

   

• inversely proportional to the voltage

• proportional to the square of the voltage

• directly proportional to the voltage