physics : class12 Galvanometer Function : Potentiometer : Current Electricity MCQ Questions and Answers
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Galvanometer Function
MCQ questions and answers.
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MCQ Questions
1. What is the main function of a galvanometer in a potentiometer circuit?
A.
To detect the presence of current
B.
To provide a constant potential difference
C.
To measure the length of the potentiometer wire
D.
To control the temperature of the circuit
Correct Answer:
To detect the presence of current
Explanation:
The galvanometer acts as a sensitive detector of current in the potentiometer circuit.
2. In a potentiometer experiment, what does zero deflection of the galvanometer indicate?
A.
The circuit is open
B.
The potential difference is balanced
C.
The current in the primary circuit is maximum
D.
The resistance of the wire is zero
Correct Answer:
The potential difference is balanced
Explanation:
Zero deflection means no current flows through the galvanometer, indicating that the potential difference being compared is balanced.
3. The galvanometer used in a potentiometer should be highly sensitive so that it can detect:
A.
Very small currents
B.
Very high temperatures
C.
Large changes in resistance
D.
The length of the connecting wires
Correct Answer:
Very small currents
Explanation:
A sensitive galvanometer is required to detect the small current that flows when the circuit is not at balance.
4. When the jockey is moved along the potentiometer wire, the galvanometer helps to locate the point where:
A.
The wire becomes hottest
B.
The current in the primary circuit is greatest
C.
The galvanometer shows zero deflection
D.
The resistance of the wire becomes infinite
Correct Answer:
The galvanometer shows zero deflection
Explanation:
The balance point is located by finding the position of the jockey at which the galvanometer shows no deflection.
5. A deflection in the galvanometer of a potentiometer indicates that:
A.
The two potential differences are unequal
B.
The potentiometer wire has no resistance
C.
The jockey is disconnected from the wire
D.
The galvanometer is acting as a battery
Correct Answer:
The two potential differences are unequal
Explanation:
Galvanometer deflection shows that a potential difference exists between its terminals, so the compared potential differences are not balanced.
6. At the balance point of a potentiometer, the current through the galvanometer is:
A.
Maximum
B.
Minimum but not zero
C.
Zero
D.
Equal to the current in the potentiometer wire
Correct Answer:
Zero
Explanation:
At balance, there is no potential difference across the galvanometer, so no current passes through it.
7. The galvanometer in a potentiometer is connected between the jockey and the:
A.
Positive terminal of the battery only
B.
Unknown potential point
C.
Switch in the primary circuit only
D.
Resistance box only
Correct Answer:
Unknown potential point
Explanation:
The galvanometer connects the jockey to the point whose potential is being compared with the potential of the potentiometer wire at the jockey position.
8. If the galvanometer deflects to one side when the jockey is moved, this shows that:
A.
Current is flowing through the galvanometer in one direction
B.
No current flows anywhere in the circuit
C.
The balance point has definitely been reached
D.
The galvanometer has infinite resistance
Correct Answer:
Current is flowing through the galvanometer in one direction
Explanation:
Deflection to one side indicates current through the galvanometer in a particular direction due to an unbalanced potential difference.
9. Why is a galvanometer preferred as a null detector in a potentiometer?
A.
It detects small currents without significantly disturbing the circuit at balance
B.
It supplies energy to the potentiometer wire
C.
It increases the resistance of the battery
D.
It measures the thickness of the potentiometer wire
Correct Answer:
It detects small currents without significantly disturbing the circuit at balance
Explanation:
The galvanometer is sensitive to small currents and shows zero current at balance, allowing an accurate comparison of potential differences.
10. If the galvanometer shows no deflection at a particular jockey position, that position is called the:
A.
Heating point
B.
Balance point
C.
Switching point
D.
Charging point
Correct Answer:
Balance point
Explanation:
The position where the galvanometer has zero deflection is known as the balance point or null point.