Explain how a moving coil galvanometer can be converted into ii a voltmeter of a given range.

A moving coil galvanometer can be converted into an ammeter by connecting a low resistance (called a shunt) in parallel to the galvanometer. A moving coil galvanometer can be converted into a voltmeter by connecting a high resistance in series with the galvanometer.A galvanometer can be converted in to a voltmeter by connecting a high resistance in series connection within it. The scale is calibrated in volt. The value of the resistance connected in series decides the range of the voltmeter.The effective resistance of the voltmeter is Rv=G+R.An ideal voltmeter must have infinite resistance. Galvanometer can be converted into voltmeter by connecting it with a very high resistance. Potential difference across the given load resistance is the sum of p.d across galvanometer and p.d. across the high resistance.A galvanometer can detect only small currents. Thus, to measure large currents it is converted into an ammeter. It can be converted into an ammeter by connecting a low resistance called shunt resistance in parallel to the galvanometer.

Explain how a moving coil galvanometer can be converted into i an ammeter

We can convert a galvanometer to an ammeter by connecting the galvanometer in parallel to a low resistance, which is known as a shunt.Thus, the galvanometer is converted to an ammeter and now can easily measure heavy currents without being fully deflected. A moving-coil galvanometer can be convertecd into a voltmeter by increasing its effective resistance by connecting a high resistance Rs in series with the galvanometer. The series resistance protects the meter and increases the range of the meter. Let G be the resistance of the galvanometer coil and Ig the current required for full-scale deflection. Let V be the maximum p.d. to be measured. Then, the series resistance Rs should be such be such that the current Ig passes through the galvanometer when the p.d. V is applied across the instrument. In the series combination, the p.d. V gets divided across the galvanometer and the resistance Rs: V=IgG+IgRs=Ig(G+Rs) &there4;Rs=VIg−G This gives the required value of the series resistance. The scale of the galvanometer is then calibrated so as to read the potential difference in volt directly.

Define Lorentz force. Derive an expression for the force on a current carrying conductor placed inside a uniform magnetic field.

The Lorentz force (or electromagnetic force) is the combination of electric and magnetic force on a point charge due to electromagnetic fields. A particle of charge q moving with a velocity v in an electric field E and a magnetic field B experiences a force of F = q E + q V × B . ∮ H . d L = I e n c .

E M B I B E

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 4 - Moving Charges and Magnetism>Nagaland Board-2018>Q 1

EASY

12th Nagaland Board

IMPORTANT

Earn 100

With the help of a diagram, explain the principle and working of a moving coil galvanometer.

Important Questions on Moving Charges and Magnetism

EASY

12th Nagaland Board

IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 4 - Moving Charges and Magnetism>Nagaland Board-2018>Q 2

Derive an expression for force per unit length between two long straight parallel current-carrying conductors. Hence, define one ampere.

MEDIUM

12th Nagaland Board

IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 4 - Moving Charges and Magnetism>Nagaland Board-2018>Q 3

Derive an expression for the torque on a rectangular current-carrying loop suspended in a uniform magnetic field.

EASY

12th Nagaland Board

IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 4 - Moving Charges and Magnetism>Nagaland Board-2019>Q 4

Deduce an expression for the magnetic dipole moment of an electron orbiting around the central nucleus.

HARD

12th Nagaland Board

IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 4 - Moving Charges and Magnetism>Nagaland Board-2019>Q 5

State Biot-Savart law. Use this law to obtain the expression for the magnetic field on the axis of a circular current loop.

HARD

12th Nagaland Board

IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 4 - Moving Charges and Magnetism>Nagaland Board-2019>Q 6

With the help of a diagram, explain the principle and working of a cyclotron. Show that cyclotron frequency does not depend on the speed of the particles.

EASY

12th Nagaland Board

IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 4 - Moving Charges and Magnetism>Nagaland Board-2020>Q 7

A strong magnetic field is applied on a stationary electron. Then the electron

EASY

12th Nagaland Board

IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 4 - Moving Charges and Magnetism>Nagaland Board-2020>Q 8

How does cyclotron increase the energy of charged particles?

EASY

12th Nagaland Board