1. What do you mean by electrical instruments?

Ans: – The instruments which are used to measure electrical quantities (such as current, voltage, power, frequency, etc) are called electrical instruments.

  1. What is meant by absolute instruments?

Ans: – The instruments which give the value of the quantity to be measured in terms of the constant of instrument are called absolute instrument.

  1. What is meant by secondary instruments?

Ans: –The deflection of such instruments gives the magnitude of electrical quantity to be measured directly.

  1. What do mean by indicating instruments?

Ans: –The instruments which indicate the magnitude of electrical quantity at the time when it is being measured.

  1. What do mean by recording instruments?

Ans: – The instruments which give a continuous record of the variations of the electrical quantity to be measured are called recording instruments.

  1. What do mean by integrating instruments?

Ans: –The instruments which measure the total quantity of electrical energy in a given time are called integrating instruments.

  1. What is deflecting torque?

Ans:- The torque due to which moving system moves from its zero  position in an indicating instrument is called deflecting torque.

  1. What do you mean by controlling torque?

Ans:- The torque which brings the pointer to zero position when instrument is disconnected from the circuit or the torque which allows the pointer to deflect in accordance to the magnitude of electrical quantity is called controlling torque.

  1. What do you mean by PMMC instrument?

Ans:- The instrument which use the permanent magnet for creating the stationary magnetic flux between which the coil moves is called PMMC instrument .

  1. What is the working principle of PMMC instrument?

Ans:- The basic principle of PMMC instrument is that when a current carrying conductor is placed in a magnetic field, a mechanical force is experienced by the  conductor.

  1. What device is used to extend the range of DC ammeter

Ans: –Shunt is used to extend the range of DC Ammeter.

  1. Which type of instrument is used to measure both AC and DC quantity?

Ans: – Moving iron instrument.