NRTC NAVEDTRA 14188A ASN 2 2026
QUESTIONS AND ANSWERS WITH
COMPREHENSIVE SOLUTIONS – FULLY
UPDATED GUARANTEED SUCCESS
Fundamentals of the Galvanometer and D'Arsonval Movement
The galvanometer and its more rugged successor, the D'Arsonval meter movement,
are the foundational instruments used to detect and measure electrical current
through the interaction of magnetic fields.
1. Basic Components and Physics
Question: What are the two basic components of a galvanometer? Answer: A
stationary permanent magnet and a movable coil.
Question: The coil in a galvanometer rotates to allow measurement of current.
Which of the following actions causes this reaction? Answer: Magnetism of
the permanent magnet and magnetism produced by current in the movable
coil. Description: This is based on the Motor Effect. When current passes through
the movable coil, it creates an electromagnet. The magnetic field of this
electromagnet interacts with the field of the permanent magnet, creating a torque
that rotates the coil.
2. The Phosphor Bronze Ribbon vs. Hairspring
Question: In a galvanometer, the phosphor bronze ribbon serves which of the
following functions? Answer: Each of the above (Provides a path for current,
supports the coil, and provides a restoring force).
Question: The phosphor bronze ribbon in the galvanometer serves the same
purpose as what component in the D'Arsonval meter? Answer: Hairspring
Description: In a standard galvanometer, the ribbon supports the coil. In the more
common D'Arsonval movement, the coil is mounted on pivots, and small
hairsprings are used to provide the restoring force (returning the needle to zero)
and to carry current into the coil.
, 3. Indicating and Directing Current
Question: In galvanometers, which of the following components is/are used to
indicate the value of the current being measured? Answer: Both 1 and 2 (A
pointer and a light beam with a mirror). Description: A pointer is common in
rugged portable meters, whereas a mirror and light beam are used in highly
sensitive laboratory galvanometers to reduce the weight of the moving parts.
Question: The direction in which the D'Arsonval meter pointer deflects
depends on what characteristic of the current applied to the coil? Answer:
Polarity Description: Because the permanent magnet's field is fixed, changing the
polarity (direction) of the current through the coil reverses the magnetic poles of
the electromagnet, causing the pointer to move in the opposite direction.
The D'Arsonval meter movement is damped to prevent which of the following
conditions? -ANSWER✔✔Oscillating readings
The weight of the rotating coil assembly and the type of bearings used in the
D'Arsonval meter are factors that affect which of the following characteristics of
the meter? -ANSWER✔✔The sensitivity
For a meter to read linearly, its face is divided into equal segments. What meter
feature makes this possible? -ANSWER✔✔The curved poles of the permanent
magnet
What is the purpose of a shunt in a dc ammeter? -ANSWER✔✔To increase the
current range of the meter
A particular D'Arsonval meter has a full-scale current reading of 1 milliampere. A
full-scale reading of 100 milliamperes may be achieved by using which of the
following components? -ANSWER✔✔A resistance of proper value placed in
parallel with the meter terminals
QUESTIONS AND ANSWERS WITH
COMPREHENSIVE SOLUTIONS – FULLY
UPDATED GUARANTEED SUCCESS
Fundamentals of the Galvanometer and D'Arsonval Movement
The galvanometer and its more rugged successor, the D'Arsonval meter movement,
are the foundational instruments used to detect and measure electrical current
through the interaction of magnetic fields.
1. Basic Components and Physics
Question: What are the two basic components of a galvanometer? Answer: A
stationary permanent magnet and a movable coil.
Question: The coil in a galvanometer rotates to allow measurement of current.
Which of the following actions causes this reaction? Answer: Magnetism of
the permanent magnet and magnetism produced by current in the movable
coil. Description: This is based on the Motor Effect. When current passes through
the movable coil, it creates an electromagnet. The magnetic field of this
electromagnet interacts with the field of the permanent magnet, creating a torque
that rotates the coil.
2. The Phosphor Bronze Ribbon vs. Hairspring
Question: In a galvanometer, the phosphor bronze ribbon serves which of the
following functions? Answer: Each of the above (Provides a path for current,
supports the coil, and provides a restoring force).
Question: The phosphor bronze ribbon in the galvanometer serves the same
purpose as what component in the D'Arsonval meter? Answer: Hairspring
Description: In a standard galvanometer, the ribbon supports the coil. In the more
common D'Arsonval movement, the coil is mounted on pivots, and small
hairsprings are used to provide the restoring force (returning the needle to zero)
and to carry current into the coil.
, 3. Indicating and Directing Current
Question: In galvanometers, which of the following components is/are used to
indicate the value of the current being measured? Answer: Both 1 and 2 (A
pointer and a light beam with a mirror). Description: A pointer is common in
rugged portable meters, whereas a mirror and light beam are used in highly
sensitive laboratory galvanometers to reduce the weight of the moving parts.
Question: The direction in which the D'Arsonval meter pointer deflects
depends on what characteristic of the current applied to the coil? Answer:
Polarity Description: Because the permanent magnet's field is fixed, changing the
polarity (direction) of the current through the coil reverses the magnetic poles of
the electromagnet, causing the pointer to move in the opposite direction.
The D'Arsonval meter movement is damped to prevent which of the following
conditions? -ANSWER✔✔Oscillating readings
The weight of the rotating coil assembly and the type of bearings used in the
D'Arsonval meter are factors that affect which of the following characteristics of
the meter? -ANSWER✔✔The sensitivity
For a meter to read linearly, its face is divided into equal segments. What meter
feature makes this possible? -ANSWER✔✔The curved poles of the permanent
magnet
What is the purpose of a shunt in a dc ammeter? -ANSWER✔✔To increase the
current range of the meter
A particular D'Arsonval meter has a full-scale current reading of 1 milliampere. A
full-scale reading of 100 milliamperes may be achieved by using which of the
following components? -ANSWER✔✔A resistance of proper value placed in
parallel with the meter terminals
