Magnetic Effects of Electric Current - Free MCQ Practice Test with solutions,

The field lines inside the solenoid are in the form of parallel straight lines. This indicates that the magnetic field is the same at all points inside the solenoid. That is, the field is uniform inside the solenoid.

Like poles of magnet repel each other and unlike poles of magnet attract each other.

An electric current through a metallic conductor produces a magnetic field around it. A long straight wire carrying a current is the simplest example of a moving charge that generates a magnetic field.

The direction of magnetic line of force is the direction of force on a North Pole, so the magnetic lines of force always begin on the North Pole of a magnet and end on the South Pole of the magnet. When a small magnetic compass is placed along a lie of force, it sets itself along the line tangential to it. Hence, the line drawn from the South Pole of the compass to its North pole shows the direction of the magnetic field.

When large current passes through a fuse, it melts quickly and breaks the circuit. Working of an electromagnet is based on the magnetic effect of electric current. An electromagnet behaves as a magnet when current passes through it. Hence, it will attract a piece of iron.

Magnetic field lines can never cross, meaning that the field is unique at any point in space. Magnetic field lines are continuous, forming closed loops without beginning or end.

Statement (1) is correct: A bar magnet has two poles - a north pole and a south pole. The magnetic field is strongest near these poles.
Statement (2) is also correct: A compass needle aligns itself with the Earth's magnetic field, and it points towards the Earth's magnetic north. This indicates the presence of a magnetic field around the Earth.
Statement (3) is incorrect: In fact, a current-carrying solenoid produces a strong magnetic field inside it. The direction of the magnetic field can be determined using the right-hand thumb rule.

Use the right hand rule. Point your thumb down. Your fingers curl toward the south when you look on the east side of the wire.

Note: An electric current cross through a straight wire. When the thumb is faced in the direction of conventional current, the curled fingers will then show in the direction of the magnetic flux lines around the conductor—the direction of the magnetic field results from this convention.

In the natural states, metals such as brass, copper , gold and silver will not attract magnets. This is because they are weak metals to start with. Magnets only attach themselves to strong metals such as iron and cobalt and that is why not all types of metals can make magnets stick to them.