back to directory
NEET PHYSICSMOVING CHARGES AND MAGNETISMEasy

Question

A millivoltmeter of 25 mV25 \text{ mV} range is to be converted into an ammeter of 25 A25 \text{ A} range. The value (in ohm) of necessary shunt will be:

A

0.001

B

0.01

C

1

D

0.05

Step-by-Step Solution

According to the sources, a galvanometer or millivoltmeter can be converted into an ammeter by connecting a low resistance called a shunt (rsr_s) in parallel . The shunt resistance is calculated using the relation rs=IgRgIIgr_s = \frac{I_g R_g}{I - I_g}, where IgRgI_g R_g is the potential difference across the instrument for full-scale deflection (VgV_g), II is the total current to be measured, and IgI_g is the current through the instrument . In this problem, Vg=25 mV=25×103 VV_g = 25 \text{ mV} = 25 \times 10^{-3} \text{ V} and the desired range I=25 AI = 25 \text{ A}. Since the current through the millivoltmeter (IgI_g) is typically negligible compared to the total current (II), the formula can be approximated as rsVg/Ir_s \approx V_g / I. Substituting the values: rs=(25×103 V)/25 A=103Ω=0.001Ωr_s = (25 \times 10^{-3} \text{ V}) / 25 \text{ A} = 10^{-3} \, \Omega = 0.001 \, \Omega.

Exam Context & Concepts Covered

This question aligns with the NEET PHYSICS syllabus, specifically targeting concepts from MOVING CHARGES AND MAGNETISM. Mastering this topic is crucial for scoring well in the upcoming medical entrance examinations. Solving conceptually related problems will help you understand the nuances of these concepts and improve your problem-solving speed.

PHYSICSMOVING CHARGES AND MAGNETISMmillivoltmeterconvertedammeternecessary

More MOVING CHARGES AND MAGNETISM Questions

View all

A uniform electric field and a uniform magnetic field are acting along the same direction in a certain region. If an electron is projected in the region such that its velocity is pointed along the direction of fields, then the electron:

A.will turn towards right of direction of motion
B.will turn towards left of direction of motion
C.speed will decrease
D.speed will increase
EasySolve

A closely wound solenoid of 2000 turns and area of cross-section $1.5 \times 10^{-4} \text{ m}^2$ carries a current of $2.0 \text{ A}$. It is suspended through its centre and perpendicular to its length, allowing it to turn in a horizontal plane in a uniform magnetic field $5 \times 10^{-2} \text{ T}$ making an angle of $30^{\circ}$ with the axis of the solenoid. The torque on the solenoid will be

A.$3 \times 10^{-3} \text{ N m}$
B.$1.5 \times 10^{-3} \text{ N m}$
C.$1.5 \times 10^{-2} \text{ N m}$
D.$3 \times 10^{-2} \text{ N m}$
EasySolve

A metallic rod of mass per unit length of 0.5 kg m⁻¹ is lying horizontally on a smooth inclined plane which makes an angle of 30° with the horizontal. The rod is not allowed to slide down by flowing a current through it when a magnetic field of induction of 0.25 T is acting on it in the vertical direction. What is the current flowing through the rod to keep it stationary?

A.7.14 A
B.5.98 A
C.14.76 A
D.11.32 A
MediumSolve

A voltmeter has a resistance of $G$ ohms and range $V$ volts. The value of resistance used in series to convert it into a voltmeter of range $nV$ volts is:

A.$nG$
B.$(n-1)G$
C.$\frac{G}{n}$
D.$\frac{G}{n-1}$
MediumSolve

The current sensitivity of a moving coil galvanometer is 5 div/mA and its voltage sensitivity (angular deflection per unit voltage applied) is 20 div/V. The resistance of the galvanometer is:

A.40 Ω
B.25 Ω
C.250 Ω
D.500 Ω
EasySolve

A long solenoid of radius $1 \text{ mm}$ has $100$ turns per mm. If $1 \text{ A}$ current flows in the solenoid, the magnetic field strength at the centre of the solenoid is:

A.$6.28 \times 10^{-4} \text{ T}$
B.$6.28 \times 10^{-2} \text{ T}$
C.$12.56 \times 10^{-2} \text{ T}$
D.$12.56 \times 10^{-4} \text{ T}$
EasySolve

A square loop ABCD carrying a current $i$ is placed near and coplanar with a long straight conductor XY carrying a current $I$. The net force on the loop will be:

A.$\frac{\mu_0 I i}{2\pi}$
B.$\frac{2\mu_0 I i L}{3\pi}$
C.$\frac{\mu_0 I i L}{2\pi}$
D.$\frac{2\mu_0 I i}{3\pi}$
HardSolve

An electron moving in a circular orbit of radius $r$ makes $n$ rotations per second. The magnetic field produced at the centre has magnitude:

A.$\frac{\mu_0 n e}{2\pi r}$
B.Zero
C.$\frac{n^2 e}{r}$
D.$\frac{\mu_0 n e}{2r}$
EasySolve

This neet physics practice question is part of the TopperSquare free question bank. TopperSquare offers 15,000+ chapter-wise NEET MCQs across Physics, Chemistry, and Biology with detailed step-by-step explanations, full mock tests, NEET PYQs (2010–2024), and an AI-powered performance analytics dashboard. browse all neet practice questions → · practice physics sets →

A millivoltmeter of $25 \text{ mV}$ range is to be... | NEET MCQ | TopperSquare