Measurement and Instrumentation
In DC potentiometer measurments, a second reading is often taken after reversing the polarities of the DC supply and the unknown voltage and the average of the two reading is taken. This is with a view of eliminate the effects of

 Stray magnetic fields.
  Stray thermal emfs.
 Ripples of the DC supply.
 Errorneous standardisation.

ANSWER DOWNLOAD EXAMIANS APP

Measurement and Instrumentation
Which of following statement are correct in case of power factor meter?

 The deflection is proportional to phase angle between field coil and crossed coil.
 Both B and C.
 The restoring torque is provided by a controlling torque.
 It consist of two coils mounted at right angles to each other.

ANSWER DOWNLOAD EXAMIANS APP