1. What is meant by the potential gradient of a potentiometer wire?
A.
Potential difference per unit length of the wire
B.
Current flowing per unit length of the wire
C.
Resistance per unit length of the wire
D.
Charge stored per unit length of the wire
Correct Answer:
Potential difference per unit length of the wire
Explanation:
Potential gradient is the potential fall along the potentiometer wire per unit length. It is given by k = V/L.
2. A potentiometer wire of length 2 m has a potential difference of 4 V across it. What is its potential gradient?
A.
0.5 V m⁻¹
B.
2 V m⁻¹
C.
4 V m⁻¹
D.
8 V m⁻¹
Correct Answer:
2 V m⁻¹
Explanation:
The potential gradient is k = V/L = 4/2 = 2 V m⁻¹.
3. For a uniform potentiometer wire, the potential difference between two points depends directly on their
A.
Temperature
B.
Separation along the wire
C.
Cross-sectional area only
D.
Terminal resistance only
Correct Answer:
Separation along the wire
Explanation:
With a uniform potential gradient, the potential difference is proportional to the length between two points: V = k l.
4. If the potential gradient of a potentiometer wire is uniform, equal lengths of the wire have
A.
Equal potential drops
B.
Different potential drops
C.
Zero potential drops
D.
Infinite potential drops
Correct Answer:
Equal potential drops
Explanation:
A uniform potential gradient means the same potential drop occurs for every equal length of the wire.
5. The SI unit of potential gradient is
A.
Volt
B.
Ohm
C.
Volt per metre
D.
Ampere per metre
Correct Answer:
Volt per metre
Explanation:
Potential gradient is potential difference divided by length, so its SI unit is V m⁻¹.
6. A 1 m long potentiometer wire has a uniform potential gradient of 0.2 V m⁻¹. What is the potential difference across the wire?
A.
0.02 V
B.
0.2 V
C.
2 V
D.
5 V
Correct Answer:
0.2 V
Explanation:
The potential difference is V = kL = 0.2 × 1 = 0.2 V.
7. A potentiometer wire has a potential difference V across a length L. Its uniform potential gradient is
A.
VL
B.
V/L
C.
L/V
D.
V + L
Correct Answer:
V/L
Explanation:
For a uniform wire, the potential gradient is the total potential difference divided by the wire length: k = V/L.
8. If the potential difference across a potentiometer wire is doubled while its length remains unchanged, its potential gradient becomes
A.
Half
B.
Unchanged
C.
Double
D.
Zero
Correct Answer:
Double
Explanation:
Since k = V/L and L is constant, doubling V doubles the potential gradient.
9. A uniform potentiometer wire has a potential gradient of 0.5 V m⁻¹. What potential difference exists between points 40 cm apart?
A.
0.02 V
B.
0.20 V
C.
0.50 V
D.
1.25 V
Correct Answer:
0.20 V
Explanation:
Converting 40 cm to 0.4 m, the potential difference is V = k l = 0.5 × 0.4 = 0.20 V.
10. For a potentiometer wire to have a uniform potential gradient, the potential drop per unit length should be
A.
Constant throughout the wire
B.
Maximum at the midpoint only
C.
Zero at one end only
D.
Different for every equal length
Correct Answer:
Constant throughout the wire
Explanation:
A uniform potential gradient means that the potential drop per unit length remains constant at all points along the wire.
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