Magnetic Effect of Current

1. A circular coil of wire of 100 turns each of radius 0.05m carries a current 0f 0.1 A Find The magnetic field at the centre of Coil

• 3.1x10-4T
• 3.1x10-5T
• 1.256x10-4T
• 3.1x10-7T

2. What current must flow in an infinitely long straight wire to give a flux density of 4.5x 10-3 T at 0.2m from the wire.

• 2345A
• 4500A
• 5678A
• 2300A

3. Two Solenoids having length L and 3L and the Number of loops 2N and 4N both have same Current Find the ratio of Magnetic Field

• 1:4
• 1:3
• 3:2
• None of these

4. A toroid has a core of inner radius 25cm and outer radius 26cm , which 3500 turns of wire are wound if the current in the wire 11A what is the magnetic Field inside the core of toroid.

• 3.02x10-2 T
• 3.02x10-3 T
• 3.02x10-4 T
• 3.02x10-5 T

5. A solenoid is 1m long and 3 cm in mean diameter. It has 5 layers of windings of 800 turns each and carries a current of 5 A. Find Magnetic Field Induction at the center of the solenoid.

• 2.5x10-1 T
• 2.5x10-3 T
• 2.5x10-4 T
• 2.5x10-2 T

6. A long straight wire carries a current of 45A , What is the magnitude of the Field at a point 10cm from the wire

• 9.0x10-5 T
• 3.5x10-11T
• 3.5x10-12T
• 3.5x10-9T

7. Find an Expression for the magnetic field induction at the centre of coil bent in the form of square of side 2a , carrying current I, in figure

• 5.656x10 -7 I/a
• 5.656x10 -9 I/a
• 5.656x10 -11 I/a
• 7.656x10 -7 I/a

8. The Following Statement is

• analogous to Kirchhoff first law
• analogous to gauss law
• analogous to law of conservation of charge
• none of these

9. A straight wire carrying current of 12 A is bent into semicircular arc of radius 2cm as shown in figures .what is the magnitude of magnetic field at the centre of arc in each case

• 2.885x10-4T
• 1.885x10-4T
• 4.885x10-5T
• 3.885x10-6T