Electromagnetism

Question 1

Word magnet

Answer 1

Magnesian Stone (Greek)
Study of magnetism started with the discovery of loadstone (magnetic iron ore or iron oxide)

Question 2

What is B?

Answer 2

Strength of magnetic field
Magnetic Induction
Magnetic flux density

Question 3

Gauss and Tesla

Gauss is the smaller unit

Answer 3

1 G = 10^-4 T

1 T = 10^4 G

Question 4

Magnetic induction

Answer 4

tells us how close together lines of force are as it tells the strength of magnetic field.

Question 5

1 T ?

1 Wb ?

Answer 5

1T = N /( A m ) = Wb/m2

1 W = Nm / A

Question 6

Ampere’s law :

Answer 6

Ampere’s circuital law given by Andre Marie Ampere in 1826.

Question 7

Permeability of free space?

Answer 7

(meu knot.) 4π × 10^-7 Wb/ (A m)

Question 8

When angle between velocity and magnetic field is between 0 and 90 the motion? (Oblique angle: acute or obtuse)

Answer 8

Spiral motion/ helical

Question 9

Time period and frequency of the particle.

Answer 9

T= 2πm/qB
f= qB/2πm

Question 10

In uniform electric and magnetic field which quantity remains constant?

Answer 10

Electric : Acceleration

Magnetic: Kinetic Energy

Question 11

Condition for velocity particles to move un-deflected through the field?

Answer 11

eE=evB

Question 12

Lorentz Force?

Answer 12

Sum of electric and magnetic force.

Responsible for gyration motion.

Question 13

When particle passes perpendicular to field without deviation, what is angle between E and B?

Answer 13

90 degrees

Question 14

Ampere’s law is applicable to ?

Answer 14

Any closed path

Question 15

B is directly proportional to I (current)

B is inversely proportional to r (radius)

Answer 15

B= k.I/r

where K = meu knot /2π

Question 16

The quantity that remains constant when charged particle enters magnetic field?

Answer 16

Kinetic energy, velocity

Question 17

Who experimented?
Changing electric field produces magnetic field.
Changing magnetic field produces electric field.

Answer 17

Oersted: Electric to Magnetic.

Faraday, Henry: Magnetic to Electric

Question 18

e/m of electron?

Answer 18

1.758 × 10^11 C/kg