Wheatstone bridge and metre bridge - One Line Questions
1.
If the resistances in the gaps of a metre bridge are swapped, and the new balance point is at 60 cm, what is the ratio of the resistances? —
1:2
2.
If the balance point in a metre bridge is found at 40 cm from the left end, and the resistance in the left gap is 10 ohms, what is the resistance in the right gap? —
15 ohms
3.
A Wheatstone bridge is used to measure an unknown resistance X. The known resistances are P=100Ω, Q=200Ω, R=300Ω. What should be the value of S for the bridge to be balanced? —
600 Ω
4.
If a resistance of 5 ohms in the left gap of a metre bridge gives a balance point at 30 cm, what is the resistance in the right gap? —
11.67 ohms
5.
In a metre bridge, if the known resistance is 100 Ω and the balance point is at 60 cm, the unknown resistance is: —
166.7 Ω
6.
The sensitivity of a Wheatstone bridge is maximum when: —
The resistances are comparable.
7.
Which of the following is a necessary condition for a Wheatstone bridge to be balanced? —
The ratio of resistances in the first two arms must be equal to the ratio of resistances in the other two arms.
8.
The condition for balancing a Wheatstone bridge (P/Q = R/S) is derived from: —
Kirchhoff's Voltage Law
9.
In a metre bridge, the resistance of the wire is not uniform. This will lead to: —
An incorrect measurement of resistance.
10.
If the galvanometer in a Wheatstone bridge shows deflection, it means the bridge is: —
Unbalanced
11.
In a Wheatstone bridge, if the battery voltage is doubled, the balance condition: —
Remains the same
12.
In a Wheatstone bridge, if the resistances P, Q, R, and S are increased by 10% each, the balance condition: —
Remains the same
13.
The wire used in a metre bridge is typically made of: —
Manganin or Eureka
14.
If the galvanometer in a Wheatstone bridge shows a deflection of 'd' when the battery polarity is reversed, and 'd'' when one of the resistances is changed, the sensitivity is related to: —
d'/d
15.
A metre bridge works on the principle of: —
Wheatstone bridge
16.
If the galvanometer resistance is very high, the current through the galvanometer when the bridge is slightly unbalanced will be: —
Low
17.
Why is Manganin or Eureka preferred for the metre bridge wire? —
High resistivity and low temperature coefficient of resistance
18.
If in a Wheatstone bridge, the galvanometer resistance is increased, it leads to: —
Decreased sensitivity.
19.
If, in a balanced Wheatstone bridge, the galvanometer resistance is increased, the sensitivity of the bridge: —
Decreases
20.
If the galvanometer resistance is very high in a Wheatstone bridge, the sensitivity: —
Decreases
21.
If the galvanometer resistance is very low in a Wheatstone bridge, the sensitivity: —
Increases
22.
If a small resistance is added in series with the galvanometer in a Wheatstone bridge, the sensitivity: —
Decreases
23.
What is the primary disadvantage of a metre bridge compared to a Wheatstone bridge? —
It is less accurate for resistances near the ends of the wire.
24.
Which of the following is a limitation of the Wheatstone bridge? —
It cannot measure very high resistances accurately.
25.
If the galvanometer shows zero deflection, it means the potential at the two terminals of the galvanometer is: —
Equal
26.
In a Wheatstone bridge circuit, if the galvanometer is replaced by a voltmeter, and the bridge is balanced, what will be the reading of the voltmeter? —
Zero volts
27.
A metre bridge is more suitable for measuring resistances in the range of: —
Ohms to a few kilo-ohms
28.
The metre bridge is less accurate for measuring resistances when the balance point is: —
Near 0 cm or 100 cm
29.
In a metre bridge, if the unknown resistance is much larger than the known resistance, the balance point will be: —
Near the 100 cm mark.
30.
Which of the following is NOT a source of error in a metre bridge experiment? —
Resistance of the galvanometer.
31.
In a metre bridge experiment, the jockey is moved along the wire until the galvanometer shows no deflection. This point is called the: —
All of the above
32.
The metre bridge is essentially a practical application of: —
The principle of Wheatstone bridge
33.
In a Wheatstone bridge, the four arms have resistances P, Q, R, and S. The bridge is balanced when: —
P/Q = R/S
34.
To measure a very low resistance using a metre bridge, one should: —
Place it in the left gap and use a low known resistance.
35.
The metre bridge can be used to measure the resistance of a galvanometer by: —
Placing it in the unknown arm and using a known resistance.
36.
In a metre bridge, the jockey should be slid gently along the wire to: —
Avoid scratching the wire and creating non-uniformity.
37.
In a metre bridge, if the unknown resistance is placed in the left gap and the known resistance is placed in the right gap, and the balance point is obtained at length L, then the unknown resistance R_x is given by: —
R_x = R_k * (L / (100-L))
38.
In a metre bridge, if the battery polarity is reversed, the balance point will: —
Remain at the same position.
39.
If the length of the metre bridge wire is increased to 2 metres, while keeping the resistances the same, the balance point will: —
Remain at the same relative position.
40.
A galvanometer is used in a Wheatstone bridge primarily to: —
Detect the presence and direction of current
41.
A Wheatstone bridge is balanced. If the galvanometer shows no deflection, it implies that: —
The current through the galvanometer is zero.
42.
The ratio of unknown resistance to known resistance in a metre bridge is equal to the ratio of: —
The length of the wire from the jockey to the left end to the length from the jockey to the right end.
43.
If one of the resistances in the Wheatstone bridge is increased, what happens to the condition for balance? —
All of the above
44.
The metre bridge is used to determine: —
The resistance of a conductor
45.
In a metre bridge experiment, an error in measuring the length L directly affects: —
The ratio of resistances.
46.
Which of the following is a direct consequence of the metre bridge wire having a uniform cross-sectional area and being made of a material with a constant resistivity? —
The resistance per unit length is constant.
47.
In a metre bridge, the terminal resistances at the ends of the wire can be neglected if: —
The balance point is near the center of the wire.
48.
Contact resistances at the ends of the metre bridge wire can cause errors in measurement. To minimize this error, the unknown resistance should be: —
Of moderate value, such that the balance point is near the center
49.
When is a Wheatstone bridge most sensitive? —
When the resistances in the arms are of comparable magnitude.
50.
If the resistances in the four arms of a Wheatstone bridge are 10 Ω, 20 Ω, 30 Ω, and 60 Ω, is the bridge balanced? —
Yes, because 10/20 = 30/60