physics : class12 Driver Cell : Potentiometer : Current Electricity MCQ Questions and Answers
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Driver Cell
MCQ questions and answers.
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MCQ Questions
1. What is the main function of the driver cell in a potentiometer?
A.
To provide a potential difference across the potentiometer wire
B.
To measure the resistance of the wire
C.
To detect the null point directly
D.
To change the length of the potentiometer wire
Correct Answer:
To provide a potential difference across the potentiometer wire
Explanation:
The driver cell supplies current through the potentiometer wire and establishes a potential gradient along it.
2. The driver cell in a potentiometer is connected in which part of the circuit?
A.
In parallel with the galvanometer
B.
In series with the potentiometer wire
C.
In parallel with the test cell
D.
In series with the voltmeter only
Correct Answer:
In series with the potentiometer wire
Explanation:
The driver cell must be connected in series with the potentiometer wire so that it drives current through the wire.
3. Which terminal of the driver cell is connected to the high-potential end of the potentiometer wire?
A.
The negative terminal
B.
The positive terminal
C.
Either terminal without any effect
D.
The terminal connected to the galvanometer
Correct Answer:
The positive terminal
Explanation:
The positive terminal of the driver cell is connected to the high-potential end to establish the correct fall of potential along the potentiometer wire.
4. What does the driver cell establish along the potentiometer wire?
A.
A magnetic field
B.
A potential gradient
C.
A constant temperature
D.
A zero current condition
Correct Answer:
A potential gradient
Explanation:
Current supplied by the driver cell produces a potential gradient along the potentiometer wire.
5. For a potentiometer to work properly, the emf of the driver cell should generally be:
A.
Zero
B.
Sufficient to send current through the potentiometer wire
C.
Less than zero
D.
Equal to the resistance of the wire
Correct Answer:
Sufficient to send current through the potentiometer wire
Explanation:
The driver cell must provide enough emf to establish current and a potential gradient in the potentiometer wire.
6. If the driver cell is disconnected from a potentiometer circuit, what happens to the potential gradient along the wire?
A.
It becomes zero
B.
It doubles
C.
It remains unchanged always
D.
It becomes equal to the emf of the galvanometer
Correct Answer:
It becomes zero
Explanation:
Without the driver cell, no current flows through the potentiometer wire, so no potential gradient is produced.
7. Which component is primarily responsible for driving current through the potentiometer wire?
A.
Galvanometer
B.
Driver cell
C.
Jockey
D.
Test cell
Correct Answer:
Driver cell
Explanation:
The driver cell supplies the electrical energy needed to drive current through the potentiometer wire.
8. In a potentiometer, the driver cell is also commonly called the:
A.
Primary source
B.
Detector
C.
Standard resistor
D.
Null instrument
Correct Answer:
Primary source
Explanation:
The driver cell acts as the primary source that supplies current to the potentiometer wire.
9. What is the effect of increasing the emf of the driver cell, while the potentiometer wire remains unchanged?
A.
The potential gradient can increase
B.
The wire becomes disconnected
C.
The galvanometer becomes the driver cell
D.
The length of the wire becomes zero
Correct Answer:
The potential gradient can increase
Explanation:
A higher emf from the driver cell can produce a larger current and hence a greater potential gradient along the wire.
10. Why is the polarity of the driver cell important in a potentiometer?
A.
It ensures that the potential falls uniformly in the required direction along the wire
B.
It changes the wire into an insulator
C.
It prevents the driver cell from supplying current
D.
It makes the galvanometer unnecessary in every measurement
Correct Answer:
It ensures that the potential falls uniformly in the required direction along the wire
Explanation:
Correct polarity makes the positive end of the wire the high-potential end and establishes the proper potential fall needed for potentiometer operation.