A
the coil experiences no torque
B
the resistance of the coil is reduced
C
the field is uniform along the axis of the coil
D
the deflecting torque is the same at every position of the coil, giving a linear scale

Q85. AI-generated practice Single-correct MCQ Medium

Which of the following does NOT increase the current sensitivity of a moving-coil galvanometer?

A
increasing the area of the coil
B
increasing the torsional constant of the spring
C
using a stronger magnetic field
D
increasing the number of turns

Q86. AI-generated practice Single-correct MCQ Hard

The number of turns of a galvanometer coil is doubled, which also doubles its resistance. The current sensitivity and voltage sensitivity respectively:

A
remain unchanged and remain unchanged
B
remain unchanged and double
C
double and double
D
double and remain unchanged

Q87. AI-generated practice Single-correct MCQ Medium

To convert a galvanometer into an ammeter, one should connect:

A
a high resistance in series with it
B
a low resistance in series with it
C
a high resistance in parallel with it
D
a low resistance in parallel with it

Q88. AI-generated practice Single-correct MCQ Medium

To convert a galvanometer into a voltmeter, one should connect:

A
a high resistance in parallel with it
B
a high resistance in series with it
C
a low resistance in parallel with it
D
a low resistance in series with it

Q89. AI-generated practice Single-correct MCQ Hard

A galvanometer of resistance 50 Ω gives full-scale deflection for 5 mA. The shunt resistance needed to convert it into an ammeter of range 0–1 A is about:

A
2.5 Ω
B
0.025 Ω
C
0.25 Ω
D
250 Ω

Q90. AI-generated practice Single-correct MCQ Hard

A galvanometer of resistance 50 Ω gives full-scale deflection for 5 mA. The resistance to be connected in series to convert it into a voltmeter of range 0–10 V is:

A
2050 Ω
B
1950 Ω
C
0.25 Ω
D
2000 Ω

Q91. AI-generated practice Single-correct MCQ Medium

A current loop of magnetic moment 0.2 A m² is in a uniform field of 0.5 T, its moment making 60° with the field. Its potential energy is:

A
−0.05 J
B
−0.1 J
C
+0.05 J
D
−0.087 J

Q92. AI-generated practice Single-correct MCQ Easy

A plane current loop behaves like a magnetic dipole. The direction of its magnetic moment is:

A
perpendicular to the plane of the loop, given by the right-hand rule
B
in the plane of the loop, along the current
C
along the line joining the loop to the north pole
D
in the plane of the loop, perpendicular to the current

Q93. AI-generated practice Single-correct MCQ Medium

A wire of fixed length is bent first into a circular loop and then into a square loop, carrying the same current each time. The ratio of the magnetic moment of the circle to that of the square is:

A
4 : π
B
2 : π
C
1 : 1
D
π : 4

Q94. AI-generated practice Single-correct MCQ Hard

The resistances of an ideal ammeter and an ideal voltmeter are respectively:

A
both zero
B
infinite and zero
C
zero and infinite
D
both infinite

Q95. AI-generated practice Numerical value Easy

A rectangular coil of 20 turns, each 5 cm × 4 cm, carries a current of 2.5 A. If its magnetic moment is x × 10^-2 A m², find x.

Q96. AI-generated practice Numerical value Medium

A coil of 100 turns, each of area 2 × 10^-3 m², carries 0.5 A in a uniform field of 0.2 T. If the maximum torque on the coil is x × 10^-3 N m, find x.

Q97. AI-generated practice Numerical value Medium

A galvanometer of resistance 99 Ω gives full-scale deflection for 1 mA. Find the shunt resistance (in ohm) needed to convert it into an ammeter of range 0–100 mA.

Q98. AI-generated practice Numerical value Hard

A galvanometer of resistance 30 Ω gives full-scale deflection for 2 mA. Find the resistance (in ohm) to be connected in series to convert it into a voltmeter of range 0–5 V.

Q99. AI-generated practice Assertion–Reason Medium

Assertion (A): A moving-coil galvanometer has a linear scale.
Reason (R): Its coil moves in a radial magnetic field, so the deflecting torque is NIAB at every position of the coil.

A
Both A and R are true and R is the correct explanation of A
B
Both A and R are true but R is not the correct explanation of A
C
A is true but R is false
D
A is false but R is true

Q100. AI-generated practice Assertion–Reason Hard

Assertion (A): Increasing the number of turns of a galvanometer coil always increases its voltage sensitivity.
Reason (R): The current sensitivity of a galvanometer is proportional to the number of turns of its coil.

A
Both A and R are true and R is the correct explanation of A
B
Both A and R are true but R is not the correct explanation of A
C
A is true but R is false
D
A is false but R is true