A magnetic field of 4 × 10 - 3 k ^ tesla exerts a force of 4 i ^ + 3 j ^ × 10 - 10 newton on a particle having a charge of 10 - 9 coulumb in X - Y plane Find the velocity of the particle.

Given Magnetic field B = 4 × 10 - 3 k ^ T Force F = 4 i ^ + 3 j ^ × 10 - 10 N Charge on the particle q = 10 - 9 C Considering the motion of the charged particle in X - direction The force on a moving charged particle is given by F = qVB Where q = charge, V = velocity of the particle and B = magnetic field. 4 i ^ + 3 j ^ × 10 - 10 = 10 - 9 V x i ^ + v y j ^ + v z k ^ 4 × 10 - 3 k ^ F x = qV y B or V y = F x qB = 4 × 10 - 10 1 × 10 - 3 × 4 × 110 - 3 = 100 m / s In Y - direction F y = qV x B or V x = F y qB = 3 × 10 - 10 1 × 10 - 3 × 4 × 110 - 3 = 75 m / s Therefore, the velocity V = V x i ^ + V y j ^ = - 75 i ^ + 100 j ^ ms - 1

In the Bohr model of the hydrogen atom, the electron circulates around the nucleus in the path of radius 5 . 1 × 10 11 m at a frequency of 6 . 8 × 10 15 Hz . Calculate the magnetic induction B at the centre of the orbit. What is the equivalent dipole moment?

Given the radius of the electron orbit r = 5 . 1 × 10 - 11 m Frequency of the electron f = 6 . 8 × 10 15 Hz . The equivalent current is I = e × f = 1 . 6 × 10 - 19 = 1 . 09 × 10 - 3 A The magnetic field due to this current at the centre of the orbit B = μ 0 × I 2 r = 4 × 10 - 7 × 1 . 09 × 10 - 3 2 × 5 . 1 × 10 - 11 = 13 . 4 web / m 2 The magnetic dipole moment = current × area of the orbit = 1 . 09 × 10 - 3 π 5 . 1 × 10 - 11 2 = 8 . 82 × 10 - 24 Am 2

How is a galvanometer converted to an ammeter?

As we know that, a galvanometer is a device that is used to detect small electric current flowing in the circuit and an ammeter is an instrument used to measure the current in a circuit. And ammeter is connected in series with the circuit. It is a low resistance instrument. A Galvanometer is converted into an ammeter by connecting a low resistance S of suitable value in parallel with the galvanometer coil. Here, S = G I g I - I g where, G = Resistance of the Galvanometer

HARD

12th Odisha Board

IMPORTANT

Earn 100

A long cylindrical wire of radius $2.5 mm$ carries a current of $1 A$ distributed uniformly over its cross-section. Find the magnitude of the magnetic field at a point inside the wire at a distance of $1 mm$ from the axis.

Important Questions on Magnetic Effect of Electric Current

MEDIUM

12th Odisha Board

IMPORTANT

Bureau's Higher Secondary Physics Class 12>Chapter 8 - Magnetic Effect of Electric Current>MODEL QUESTIONS>Q 13

A long solenoid has closely wound turns such that the successive turns nearly touch each other but well insulated. If the wire used in the solenoid has a radius of

0.5 mm

, find the magnetic field at the centre of the solenoid, when it carries a current of

5 A

HARD

12th Odisha Board

IMPORTANT

Bureau's Higher Secondary Physics Class 12>Chapter 8 - Magnetic Effect of Electric Current>MODEL QUESTIONS>Q 14

A magnetic field of

4 \times 10^{- 3} \hat{k} tesla

exerts a force of

(4 \hat{i} + 3 \hat{j}) \times 10^{- 10} newton

on a particle having a charge of

10^{- 9} coulumb

X - Y

plane Find the velocity of the particle.

HARD

12th Odisha Board

IMPORTANT

Bureau's Higher Secondary Physics Class 12>Chapter 8 - Magnetic Effect of Electric Current>MODEL QUESTIONS>Q 15

A rectangular coil of

100 turns

and length of

5 cm

and width

4 cm

is suspended in a uniform magnetic field with its plane parallel to the field. A torque of

0.2 N m

acts on the coil when a current of

0.2 A

is maintained in it. Find the magnitude of the magnetic field.

HARD

12th Odisha Board

IMPORTANT

Bureau's Higher Secondary Physics Class 12>Chapter 8 - Magnetic Effect of Electric Current>MODEL QUESTIONS>Q 16

A moving coil galvanometer has a resistance of

30 ohm

, through a current of

1 m A

flows. Find the value of multiplier resistance to be used with the galvanometer to convert it to a voltmeter of the range

2.5 V

HARD

12th Odisha Board

IMPORTANT

Bureau's Higher Secondary Physics Class 12>Chapter 8 - Magnetic Effect of Electric Current>MODEL QUESTIONS>Q 16

A moving coil galvanometer has a resistance of

30 ohm

, through a current of

1 m A

flows. Find the value of multiplier resistance to be used with the galvanometer to convert it to a voltmeter of the range

10 V

HARD

12th Odisha Board

IMPORTANT

Bureau's Higher Secondary Physics Class 12>Chapter 8 - Magnetic Effect of Electric Current>MODEL QUESTIONS>Q 17

A rigidly supported long horizontal wire carries a current

I_{a} = 100 A

. Directly above and parallel to it is a fine wire that carries a current

I_{b} = 20 A

and weigh

0.073 N / m

. How far above the lower wire should this second wire be strung so that it may be supported by magnetic repulsion (assume the diameter of the wire is small)

HARD

12th Odisha Board

IMPORTANT

Bureau's Higher Secondary Physics Class 12>Chapter 8 - Magnetic Effect of Electric Current>MODEL QUESTIONS>Q 18

Two parallel wires separated by

2 m

carry currents of

3 A

each in the opposite directions. Find the magnetic induction for the points between the wires at a distance

50 cm

from each wire.

HARD

12th Odisha Board

IMPORTANT

Bureau's Higher Secondary Physics Class 12>Chapter 8 - Magnetic Effect of Electric Current>MODEL QUESTIONS>Q 19

In the Bohr model of the hydrogen atom, the electron circulates around the nucleus in the path of radius

5.1 \times 10^{11} m

at a frequency of

6.8 \times 10^{15} Hz

. Calculate the magnetic induction B at the centre of the orbit. What is the equivalent dipole moment?

A long cylindrical wire of radius 2.5 mm carries a current of 1A distributed uniformly over its cross-section. Find the magnitude of the magnetic field at a point inside the wire at a distance of 1 mm from the axis.

Important Questions on Magnetic Effect of Electric Current

Learn and Prepare for any exam you want !

A long cylindrical wire of radius $2.5 mm$ carries a current of $1 A$ distributed uniformly over its cross-section. Find the magnitude of the magnetic field at a point inside the wire at a distance of $1 mm$ from the axis.