physics : class12 Jockey Function : Potentiometer : Current Electricity MCQ Questions and Answers
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Jockey Function
MCQ questions and answers.
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MCQ Questions
1. What is the main function of the jockey in a potentiometer?
A.
To slide along the potentiometer wire and make electrical contact at different points
B.
To increase the resistance of the battery
C.
To measure the current directly in the circuit
D.
To produce the potential difference across the wire
Correct Answer:
To slide along the potentiometer wire and make electrical contact at different points
Explanation:
The jockey is a movable contact that touches different points on the potentiometer wire to select different lengths of wire.
2. How is the jockey generally moved on a potentiometer wire?
A.
By sliding it along the wire
B.
By rotating the battery terminals
C.
By heating the wire
D.
By disconnecting the galvanometer
Correct Answer:
By sliding it along the wire
Explanation:
The jockey is designed to move or slide along the potentiometer wire so that contact can be made at different positions.
3. What does the jockey select in a potentiometer circuit?
A.
A particular length of the potentiometer wire
B.
The chemical composition of the electrolyte
C.
The strength of the battery permanently
D.
The resistance of the galvanometer coil
Correct Answer:
A particular length of the potentiometer wire
Explanation:
By changing its position, the jockey selects the length of wire between the fixed end and the contact point.
4. During a potentiometer experiment, the jockey is connected to the galvanometer through its:
A.
Metallic contact point
B.
Insulating handle only
C.
Battery casing
D.
Wooden support
Correct Answer:
Metallic contact point
Explanation:
The metallic tip of the jockey makes electrical contact with the potentiometer wire and connects the selected point to the galvanometer circuit.
5. Why should the jockey be touched lightly on the potentiometer wire?
A.
To avoid damaging the wire and changing its resistance
B.
To increase the length of the wire automatically
C.
To make the battery voltage zero
D.
To prevent the galvanometer from being connected
Correct Answer:
To avoid damaging the wire and changing its resistance
Explanation:
Pressing the jockey too hard can damage the wire or alter its contact, affecting the potentiometer reading.
6. What happens when the jockey is moved to another point on the potentiometer wire?
A.
The length of wire used in the measuring circuit changes
B.
The battery is permanently disconnected
C.
The wire becomes an insulator
D.
The galvanometer is removed from the circuit
Correct Answer:
The length of wire used in the measuring circuit changes
Explanation:
Moving the jockey changes the contact point and therefore changes the length of potentiometer wire included in the circuit.
7. In a potentiometer, the position of the jockey is adjusted to find the point where the galvanometer shows:
A.
Zero deflection
B.
Maximum brightness
C.
Constant heating
D.
A fixed resistance
Correct Answer:
Zero deflection
Explanation:
The jockey is moved until the galvanometer shows zero deflection, indicating the balance point.
8. At the balance point, what does the jockey indicate on the potentiometer wire?
A.
The point where the potential difference balances the unknown voltage
B.
The point where the wire has no resistance
C.
The point where the battery stops supplying current
D.
The point where the galvanometer has maximum current
Correct Answer:
The point where the potential difference balances the unknown voltage
Explanation:
The jockey marks the balance point where the potential drop along the selected wire length equals the potential difference being measured.
9. Which part of the jockey actually touches the potentiometer wire?
A.
Its conducting metal tip
B.
Its plastic handle
C.
Its insulating base
D.
Its connecting cord insulation
Correct Answer:
Its conducting metal tip
Explanation:
The conducting metal tip is used to make electrical contact with the wire while the handle allows the jockey to be moved safely.
10. If the jockey is moved toward the end of the potentiometer wire, what is directly changed?
A.
The contact position on the wire
B.
The emf of the battery
C.
The number of turns in the galvanometer
D.
The material of the wire
Correct Answer:
The contact position on the wire
Explanation:
The basic function of the jockey is to change its contact position along the wire, allowing different wire lengths to be selected.