Magnetic Field Due to Current through a Circular Loop

Q.

The factors that affect the strength of a magnetic field at a point due to a straight current carrying conductor are:

1. Magnitude of the electric current

2. Perpendicular distance between the point and the conductor

3. Both (a) and (b)

4. None of these

Q. The magnetic field at the centre of a circular coil of radius r carrying current I is $B_1$. The field at the centre of another coil of radius 2r carrying the same current I is $B_2$. The ratio $\frac{B_1}{B_2}$ is

1. $\frac{1}{2}$
2. 1
3. 2
4. 4

Q. How is the strength of magnetic field affected when current increases?

Q. Find the magnetic field at the centre of the circular loop shown in the figure.

1. $\frac{{\mu }_{0}i}{2r}$
2. $\frac{{\mu }_{0}i\pi }{2r}$
3. $\frac{{\mu }_{0}i}{2r}\left[\frac{\pi -1}{\pi }\right]$
4. $\frac{{\mu }_{0}i}{r}$

Q.

The front face of a circular wire carrying current behaves like a north pole. The direction of current in this face of the circular wire is :

(a) clockwise (b) downwards (c) anticlockwise (d) upwards

Q.

What is the direction of magnetic field at the centre of a coil carrying current in (i) the clockwise, (ii) the anticlockwise, direction?

Q.

(a) Draw the magnetic lines of force due to a circular wire carrying current.

(b) What are the various ways in which the strength of the magnetic field produced by a current-carrying circular coil can be increased ?

Q. At every point of a current-carrying circular loop, the concentric circles representing the magnetic field around it would become larger and larger as we move away from the wire. True or false?

1. False
2. True

Q.

A conducting loop is placed in a uniform magnetic field, with its plane perpendicular to the field. An emf is induced in the loop if

1. It is rotated about its axis

2. It is rotated about its diameter

3. It is not moved

4. It is given translational motion in the field

Q.

Option 25
Why does a magnetic compass needle pointing north and south in the absence of a nearby magnet gets deflected when a bar magnet or a current carrying loop is brought near to it. Describe some salient features of magnetic lines of field concept.

Q.

The magnetic field line passing through the centre of a circular current carrying conductor is a straight line.

1. True

2. False

Q.

Explain magnetic effects of electric current briefly

( whole chapter )

Q.

A wire, bent into a circle, carries a current in an anticlockwise direction. What polarity does this face of the coil exhibit ?

Q. State the factors on which the magnitude of the magnetic field due to a current-carrying conductor depends and how it depends.

Q. A wire as shown in the figure carries a current of 2A.The semicircle has radius of 4cm, the magnetic field at the center C will be

1. $\frac{3\pi }{2}\times {10}^{-7}T$
2. $\frac{4\pi }{3}\times {10}^{-7}T$
3. $\frac{\pi }{2}\times {10}^{-5}T$
4. $\frac{6\pi }{5}\times {10}^{-5}T$

Q. Which of the following factors regarding solenoid is/are incorrect?

I.The current flowing in a solenoid is inversely proportional to the strength of the magnetic field: $B\alpha \frac{1}{I}$

II.The number of turns of wire forming the solenoid is directly proportional to the magnetic field $B\alpha n$

III.The magnetic field of a solenoid depends on the nature of material inside the salenoid as $B\alpha \frac{1}{\mu }$ where $\mu$ is the permeability of the material.

1. I & II
2. II & III
3. I & III
4. All of these

Q.

The magnetic field strength of a loop is greater when the number of loops in the coil is higher.

1. True

2. False

Q.

The directions of current flowing in the coil of a electromagnet at its ends X and Y are as shown below :

(a) What is the polarity of end X ?

(b) What is the polarity of end Y ?

(c) Name and state the rule which you have used to determine the polarities.

Q. If the current is flowing anticlockwise in a circular coil placed in the plane of paper as shown in the figure, then the direction of lines of force inside the coil is ?

1. Away from you
2. Towards you
3. Towards the centre of the coil along the radius
4. Away from the centre of the coil along the radius

Q.

The back face of a circular loop of wire is found to be south magnetic pole. The direction of current in this face of the circular loop of wire will be :

(a) towards south (b) clock wise (c) anticlockwise (d) towards north

Q.

State true or false.
The magnetic field line passing through the centre of a circular current carrying conductor is a straight line.

1. True

2. False

Q. The net magnitude of magnetic field at point O is

1. 
2. 
3. 
4. 

Q. A and B are two concentric circular conductors of centre O and carrying current $I_{1}and{I}_2$ as shown in the figure.$B_{1}and{B}_2$ are magnitudes of magnetic field due to A and B respectively. The net magnetic field at point O is

1. 
   $B_1+B_2$
2. 
   $B_1-B_2$
3. 
   $B_2\times B_1$
4. 
   $\frac{B_2}{B_1}$

Q. When a soft iron core is introduced in a coil, the strength of the magnetic field:

1. increases
2. decreases
3. remains the same
4. will become 0

Q. A wire loop is formed by joining two semi-circular wires of radii $R_{1}and{R}_2$ carrying current I as shown in the given diagram. The magnitude of net magnetic field at the centre O is

1. $\frac{{\mu }_{0}l\pi }{4\pi R_1}$
2. $\frac{{\mu }_{0}l\pi }{4\pi R_2}$
3. $\frac{{\mu }_{0}l\pi }{4\pi }[\frac{1}{R_1}-\frac{1}{R_2}]$
4. $\frac{{\mu }_{0}l\pi }{4\pi }[\frac{1}{R_1}+\frac{1}{R_2}]$

Q.

The magnetic field strength at a point due to a current carrying circular wire depends on

1. the magnitude of current flowing through the wire

2. the distance of the point from the wire

3. all the above

4. the number of loops the wire has

Q.
The magnetic field inside a long straight solenoid-carrying current

1. is zero
2. decreases as we move towards its end
3. increases as we move towards its end
4. is the same at all points

Q.

With the help of a labeled diagram, explain the distribution of magnetic field due to current through a circular coil.

Q.

Give the factors that affect strength of magnetic field at a point due to a straight conductor carrying current. [3 MARKS]

Q. Describe in brief an activity to study the magnetic field lines due to a current carrying circular coil.

[5 Marks]
[CBSE Board Term I, 2017, 2016]
[Magnetic Field Due to a Circular Current Carrying Conductor]