Bissoy.com
Doctors Medicines MCQs Q&A

A moving coil instrument has a resistance of 70 Ω and gives full scale deflection of 100 scale divisions for a current of 1 mA. The instrument is connected in parallel with a shunt of 30 Ω resistance and this combination is then connected in series with a load and supply. Determine the current in the load when the instrument gives an indication of 80 scale divisions.

A moving coil instrument has a resistance of 70 Ω and gives full scale deflection of 100 scale divisions for a current of 1 mA. The instrument is connected in parallel with a shunt of 30 Ω resistance and this combination is then connected in series with a load and supply. Determine the current in the load when the instrument gives an indication of 80 scale divisions. Correct Answer 2.66 mA

Concept:

The shunts for moving iron instrument shown below:

[ alt="F1 Tapesh 1.6.21 Pallavi D16" src="//storage.googleapis.com/tb-img/production/21/06/F1_Tapesh_1.6.21_Pallavi_D16.png" style="width: 292px; height: 248px;">

Calculation:

The instrument current is:

I1 = (80/100) × 1 mA

I1 = 0.8 mA

The shunt resistance is 0.43 part of the meter resistance. So, the current will increase 2.33 times.

I2 = 0.8 mA × 2.33

I2 = 1.866 mA

The total current is I1 + I2 = I

I = 0.8 + 1.866 mA

I = 2.66 mA

Related Questions

When an electric current coil of a wattmeter is connected to the electric current path R and the voltage coil is connected between the electric current R path and the neutral side of the balanced three phase supply, it shows 10 kW. The line voltage along the phase sequence RYB is 400 V. The current drawn by the current path is 54 A. What is the new reading of the wattmeter if the voltage coil is connected between the lines B and the Y paths, even if the electric current coil is continuously present in the line R?
A 100KW, 250 V, 400 A, a long shunt compound generator has an armature resistance of 0.025 ohms. There are 1000 shunt fields turns per pole and 3 series field turns per pole. The series field is connected in a such a fashion that positive armature current produces direct-axis MMF which adds to that of the shunt field. Compute the gross MMF at the rated terminal current when shunt field current is 4.7A and speed is 1150 rpm.
The figure below shows a circuit for an AC voltmeter. It utilizes a moving-coil meter that gives a full-scale reading when the average current flowing through it is 1 mA. The moving-coil meter has a 50-Ω resistance. The value of R that results in the meter indicating a full-scale reading when the input sine-wave voltage VI is 20 V peak-to-peak is
The full-scale deflection current of an ammeter is 1 mA and its internal resistance is 100 ohms. If this meter is to have full deflection at 5A, what is the value of the shunt resistance to be used?
A permanent magnet moving coil ammeter has a coil resistance of 99ohm and Full Scale DeflectionFSD. current of 0.1mA. Shunt resistance is 1 ohm. Current through the meter at 0.5 F.S.D is
Consider the following statements in connection with deflection-type and null-type instruments: 1. Null-type instruments are more accurate than the deflection-type ones. 2. Null-type of instrument can be highly sensitive compared to a deflection-type instrument. 3. Under dynamic conditions, null-type instruments are less preferred to deflection-type instruments. 4. Response is faster in null-type instruments as compared to deflection-type instruments. Which of the above statements are correct?
A certain current on passing through a galvanometer produces a deflection of 100 divisions. When a shunt of one ohm is connected, the deflection reduces to 1 division. The galvanometer resistance is
Z1 and Z2 are connected in series to form a load. A wattmeter’s current coil is connected in series with the load, whereas its pressure coil is connected across Z2. The wattmeter reads:
The full-scale deflection current of an ammeter is 1 mA and its internal resistance is 100 ohms. This is to have full deflection when 100V is measured. What is the value of series resistor to be used?
একটি স্টেপ আপ ট্রান্সফরমারে, গৌণ কুণ্ডলীর পাকসংখ্যা মুখ্য কুন্ডলীর পাকসংখ্যার দ্বিগুণ। যদি মূখ্য কুন্ডলীকে কোন পরিবর্তী বিদ্যুৎ লাইনের সাথে সংযুক্ত করা হয়, তাহলে মুখ্য কুণ্ডলীর তুলনায় গৌণ কুণ্ডলীতে- (In a step up transformer, the number of turns in the secondary coil is twice to that of primary coil. If you apply an alternating current in the primary coil, then in the secondary coil compared to the primary coil-)