1. The potential gradient of a potentiometer wire is defined as:
A.
Potential drop 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 drop per unit length of the wire
Explanation:
Potential gradient is the potential difference developed per unit length of the potentiometer wire. It is given by k = V/L.
2. A potentiometer wire has a potential difference of 2 V across a length of 4 m. What is its potential gradient?
A.
0.25 V m⁻¹
B.
0.5 V m⁻¹
C.
2 V m⁻¹
D.
8 V m⁻¹
Correct Answer:
0.5 V m⁻¹
Explanation:
The potential gradient is k = V/L = 2/4 = 0.5 V m⁻¹.
3. What is the SI unit of potential gradient?
A.
Volt
B.
Ohm
C.
Volt per metre
D.
Ampere per metre
Correct Answer:
Volt per metre
Explanation:
Since potential gradient is potential difference divided by length, its SI unit is volt per metre (V m⁻¹).
4. If the potential difference across a potentiometer wire is doubled while its length remains unchanged, the potential gradient becomes:
A.
Half its original value
B.
Twice its original value
C.
Unchanged
D.
Zero
Correct Answer:
Twice its original value
Explanation:
Using k = V/L, doubling V while keeping L constant doubles the potential gradient.
5. If the length of a potentiometer wire is doubled while the potential difference across it remains constant, the potential gradient becomes:
A.
Twice its original value
B.
Four times its original value
C.
Half its original value
D.
Unchanged
Correct Answer:
Half its original value
Explanation:
The potential gradient is k = V/L. Therefore, doubling the length with constant potential difference makes the gradient half.
6. A uniform potentiometer wire has a potential gradient of 0.02 V cm⁻¹. What potential difference is measured across 5 cm of the wire?
A.
0.004 V
B.
0.01 V
C.
0.1 V
D.
2.5 V
Correct Answer:
0.1 V
Explanation:
The potential difference is V = kL = 0.02 × 5 = 0.1 V.
7. For a uniform potentiometer wire, the potential drop across equal lengths is:
A.
Equal
B.
Always zero
C.
Greater for the shorter length
D.
Randomly different
Correct Answer:
Equal
Explanation:
In a uniform wire, the potential gradient is constant, so equal lengths have equal potential drops.
8. A 100 cm potentiometer wire has a potential difference of 5 V across it. What is the potential gradient in V cm⁻¹?
A.
0.05 V cm⁻¹
B.
0.5 V cm⁻¹
C.
5 V cm⁻¹
D.
500 V cm⁻¹
Correct Answer:
0.05 V cm⁻¹
Explanation:
The potential gradient is k = V/L = 5/100 = 0.05 V cm⁻¹.
9. The potential gradient of a potentiometer wire is 0.1 V m⁻¹. What potential difference exists across 3 m of the wire?
A.
0.03 V
B.
0.1 V
C.
0.3 V
D.
3 V
Correct Answer:
0.3 V
Explanation:
The potential difference is V = kL = 0.1 × 3 = 0.3 V.
10. Which expression gives the potential gradient k for a potentiometer wire of length L having potential difference V across it?
A.
k = VL
B.
k = V/L
C.
k = L/V
D.
k = V + L
Correct Answer:
k = V/L
Explanation:
Potential gradient is defined as potential difference per unit length, so k = V/L.
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