Test: Magnetic Effects of Electric Current - 2 - UPSC MCQ

The region around a magnet, in which its influence can be felt, is called its magnetic field

Let a constant current I flows through a horizontal wire from east to west. The direction of magnetic field, as per right-hand thumb rule, will be from north to south at a point directly below the current-carrying wire.

The direction of magnetic field developed around a current-carrying conductor can be found by the use of right-hand thumb rule.

The strength of the magnetic field around a current-carrying straight conductor is directly proportional to the amount of current flowing in the conductor.

The strength of a magnetic field inside a long, current-carrying, straight solenoid is uniform at all points. Moreover, the field depends on the amount of current flowing and the number of turns in solenoid coil besides its length

It is most important method for protecting the electrical devices from short circuiting or overloading by stopping the flow of any large electric current exceeds from its rating.

Answer:

-ve  z axis

Explanation:

We use left hand rule or right hand palm rule or  cockscrew rule

as electron moves in positive x axis the current I is in -ve x axis

B is in +ve y axis

then -ve z axis is the direction of lorentz force

or u can just use vector cross product [-i x j ] = -k

The strength of magnetic field along the axis of a solenoid coil increases on increasing the current flowing through the solenoid coil and on increasing the number of turns in the solenoid coil. Moreover, if a soft iron core is inserted inside the solenoid coil then magnetic field increases many fold.

A current carrying solenoid produces a uniform magnetic field inside it.

When a current-carrying straight conductor is placed perpendicular to the direction of a uniform magnetic field, it experiences a mechanical force. The direction of mechanical force is given by Fleming’s left-hand rule.

Using electromagnet, the magnetic field strength further increase by increasing the current. Hence it will enhance the power of electric.

On applying Fleming’s left-hand rule we find that both electron as well as proton experience forces pointing into the plane of paper.

A solenoid behaves like a bar magnet. Hence the pattern of magnetic field associated with solenoid and around the bar magnet is same.

Like magnetic poles (say N- and N-poles) always repel each other.

- When a circuit carrying current is closed, it generates a magnetic field around it.
- According to Ampère's circuital law and the right-hand rule, the magnetic field lines around a straight current-carrying conductor form concentric circles.
- These circles are centered on the wire, and their planes are perpendicular to the direction of the current.
- Therefore, on a horizontal plane like ABCD, the magnetic field lines appear as concentric circles, making option A correct.