1. If the potential gradient along a potentiometer wire is k, the potential difference across a length l is
A.
V = k/l
B.
V = kl
C.
V = k + l
D.
V = l/k
Correct Answer:
V = kl
Explanation:
The potential difference is equal to the potential gradient multiplied by the length, so V = kl.
2. The potential gradient of a potentiometer wire is defined as the potential drop per unit
A.
current
B.
resistance
C.
length
D.
area
Correct Answer:
length
Explanation:
Potential gradient is the potential difference divided by the length of the wire, represented as k = V/l.
3. For a uniform potentiometer wire carrying constant current, equal lengths of the wire have
A.
equal potential drops
B.
unequal potential drops
C.
zero potential drops
D.
equal currents only at the ends
Correct Answer:
equal potential drops
Explanation:
A uniform wire has a constant potential gradient, so equal lengths produce equal potential drops.
4. A potentiometer wire has a potential gradient of 0.02 V per metre. The potential drop across 3 metres is
A.
0.006 V
B.
0.02 V
C.
0.06 V
D.
0.6 V
Correct Answer:
0.06 V
Explanation:
Using V = kl, the potential drop is 0.02 V/m × 3 m = 0.06 V.
5. If the length of a uniform potentiometer wire used for measurement is doubled, its potential drop becomes
A.
half
B.
double
C.
unchanged
D.
zero
Correct Answer:
double
Explanation:
Since potential drop is directly proportional to length for a uniform wire, doubling the length doubles the potential drop.
6. For a uniform potentiometer wire, the potential gradient remains constant when the
A.
current through the wire is steady
B.
wire is cut into pieces
C.
length is made zero
D.
wire is disconnected from the source
Correct Answer:
current through the wire is steady
Explanation:
A steady current through a uniform wire produces a constant potential gradient along its length.
7. If a potential difference V is balanced by a length l of a potentiometer wire, the potential gradient is
A.
V + l
B.
Vl
C.
V/l
D.
l/V
Correct Answer:
V/l
Explanation:
Potential gradient is defined as potential difference per unit length, so k = V/l.
8. The potential drop across a zero-length portion of an ideal uniform potentiometer wire is
A.
maximum
B.
equal to the total voltage
C.
zero
D.
one volt
Correct Answer:
zero
Explanation:
Since V = kl, a portion with zero length has zero potential drop.
9. A potentiometer wire has a total potential difference of 2 V across a length of 10 m. Its potential gradient is
A.
0.02 V/m
B.
0.2 V/m
C.
2 V/m
D.
20 V/m
Correct Answer:
0.2 V/m
Explanation:
The potential gradient is k = V/l = 2 V/10 m = 0.2 V/m.
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