Electromagnetism

Question 1

What is a magnetic field

Answer 1

It is a region of space where a magnetic pole experiences a force

Question 2

The direction of the magnetic field in a current carrying wires is found using _______

Answer 2

Right-hand grip rule

Question 3

What is the magnetic flux density B at a point at distance r from a wire

Answer 3

B = (μ.I)/(2πr)

Question 4

What is the magnetic flux density at the centre of a flat coil of N turns and radius r

Answer 4

B = (μ.NI)/2r

Question 5

What is the magnetic flux density along the axis of a long solenoid of n turns and length l

Answer 5

B = μ.nl

Magnetic flux density along the same axis at the ends of the solenoid is half of that at the centre

Question 6

Direction of the B-field in a solenoid can be found using _______

Answer 6

right hand grip rule

Question 7

What is the force on a current carrying conductor in a B-field

Answer 7

F = BIL sinθ

Direction of the force F relative can be predicted using Fleming’s left-hand rule.

- Thumb: Force
- Index: Field
- Middle: Current

Question 8

What is magnetic flux density

Answer 8

Magnetic flux density at a point is defined as the force acting per unit current per unit length of a conductor when the conductor is placed at right angles to the field

B=F/IL

Question 9

What is the force on a moving charge in a magnetic field

Answer 9

F = Bqv sinθ

Question 10

What is the radius and period of the orbit of a charge in a magnetic field

Answer 10

r=mv/Bq

T = 2πm/Bq