Question 1

Two straight rods 55 cm long and 1.4 mm apart in a current balance carry current I,each in opposite directions.If a mass of 1.3 g when placed on the upper rod balances the magnetic force of repulsion between the rods,then calculate the current I.

Accepted Answer

A) 160 A 
B) 18 A 
C) 13 A 
D) 3.6 A 
E) 9.0 A

Question 2

At great axial distances x from a current-carrying loop the magnetic field varies as

Accepted Answer

A) x2  
B) x-3  
C) x-2  
D) x3  
E) x-1

Question 3

Calculate the magnetic field at the center of a circular current loop of area 0.200 m2 divided by the magnetic field at the center of a square current loop of the same inside area for the same current I value.

Accepted Answer

A) 1.00 
B) 1.02 
C) 0.246 
D) 0.985 
E) 0.785

Question 4

Use the following figure to answer the next problem: 
-The tightly wound toroid shown consists of 100 turns of wire,each carrying a current I = 3 A.If a = 12 cm and b = 15 cm,the magnetic field at r = 10 cm,due to the current in this toroid,is (µ0 = 4$\pi$ $\times$ 10-7 N/A2)

Accepted Answer

A) 400 µT 
B) 500 µT 
C) 600 µT 
D) zero 
E) impossible to calculate without additional information.

Question 5

A toroid has 200 turns of wire with a current of 3 A passing through the wire.The inner radius of the toroid is 3 cm and the outer radius is 5 cm.Calculate the magnetic field strength at a radius of 2 cm.

Accepted Answer

A) 6.0 $\times$ 10-3 T 
B) 3.0 $\times$ 10-3 T 
C) 1.2 $\times$ 10-2 T 
D) 4.8 $\times$ 10-4 T 
E) none of the above

Question 6

A wire of radius 0.35 cm carries a current of 75 A that is uniformly distributed over its cross-sectional area.The magnetic field  at a distance of 5.0 cm from the center of the wire is approximately

Accepted Answer

A) 0.47 mT 
B) 1.5 mT 
C) 0.30 mT 
D) 0.56 mT 
E) 0.24 mT

Exam 27: Sources of the Magnetic Field

Two straight rods 55 cm long and 1.4 mm apart in a current balance carry current I,each in opposite directions.If a mass of 1.3 g when placed on the upper rod balances the magnetic force of repulsion between the rods,then calculate the current I.

At great axial distances x from a current-carrying loop the magnetic field varies as

Calculate the magnetic field at the center of a circular current loop of area 0.200 m² divided by the magnetic field at the center of a square current loop of the same inside area for the same current I value.

A toroid has 200 turns of wire with a current of 3 A passing through the wire.The inner radius of the toroid is 3 cm and the outer radius is 5 cm.Calculate the magnetic field strength at a radius of 2 cm.

A wire of radius 0.35 cm carries a current of 75 A that is uniformly distributed over its cross-sectional area.The magnetic field at a distance of 5.0 cm from the center of the wire is approximately

Exam 27: Sources of the Magnetic Field

Two straight rods 55 cm long and 1.4 mm apart in a current balance carry current I,each in opposite directions.If a mass of 1.3 g when placed on the upper rod balances the magnetic force of repulsion between the rods,then calculate the current I.

At great axial distances x from a current-carrying loop the magnetic field varies as

Calculate the magnetic field at the center of a circular current loop of area 0.200 m2 divided by the magnetic field at the center of a square current loop of the same inside area for the same current I value.

Use the following figure to answer the next problem: -The tightly wound toroid shown consists of 100 turns of wire,each carrying a current I = 3 A.If a = 12 cm and b = 15 cm,the magnetic field at r = 10 cm,due to the current in this toroid,is (µ0 = 4 π\piπ ×\times× 10-7 N/A2)

A toroid has 200 turns of wire with a current of 3 A passing through the wire.The inner radius of the toroid is 3 cm and the outer radius is 5 cm.Calculate the magnetic field strength at a radius of 2 cm.

A wire of radius 0.35 cm carries a current of 75 A that is uniformly distributed over its cross-sectional area.The magnetic field at a distance of 5.0 cm from the center of the wire is approximately

Calculate the magnetic field at the center of a circular current loop of area 0.200 m² divided by the magnetic field at the center of a square current loop of the same inside area for the same current I value.