Test: Magnetic Effects of Electric Current- 3 - UPSC MCQ

The correct answer is B as e electric current through the copper wire has produced a magnetic . In 1820 he accidentally discovered that a compass needle got deflected ... Through this observation Oersted showed that electricity and . representing the magnetic field around a current-carrying straight wire.

The magnetic field around a straight current carrying conductor or wire can be increased by bending the wire into circular loop. A circular loop is made up of large number of very small straight wires.A magnetic field is produced by an electric current flowing through a circular coil of wire.Each small section of current carrying wire contributes to magnetic field lines. At the centre of circular wire,field lines become straight and perpendicular to the plane of coil.Right hand thumb rule is used to determine the direction of magnetic field produced due to current carrying circular wire.

When current flows through a straight conductor, it is said that the current is straight. The magnetic field produced due to a straight current carrying conductor is in the form of concentric circles. The centre of the circles lies on the conductor itself and are in the plane perpendicular to the straight conductor. This implies that the magnetic field produced due to straight current is circular.

Clock rule states that if the current at any face of the loop flows in clockwise direction, that face behaves like a south pole. And, if the current round any face of the loop is in anti-clockwise direction, that face behaves like a north pole. 

The polarity of this magnet can be understood with the help of clock face rule. If the current is flowing in anti-clockwise direction, then the face of the loop shows North pole.

A simple electromagnet can be created by wrapping a coil of wire around a soft iron  The magnetic field strength of an electromagnet is therefore determined by the  turns of wire in the coil the greater will be the strength of the magnetic field. 

In an electric generator mechanical energy is used to rotate a conductor in a magnetic field to produce electricity. Fleming's right hand rule is used where motion and magnetic field is given and the current is induced.

The fuse wire is always connected in the live wire of the circuit because if the fuse is put in the neutral wire, then due to excessive flow of current when the fuse burns, current stops flowing in the circuit, but the appliance remains connected to the high potential point of supply through the live wire .

Electric and main switch is contained in a main board fitted usually in varandah or poarch . Because it will be safe there. 

The bigger hole is connected to the earth wire and the other two holes are connected to the live wire and neutral wire respectively.

When live wire comes in direct contact with the neutral wire the very high current flows through the circuit producing a large amount of heat. This phenomenon is called the Short Circuit.

The field consists of concentric circles centred on the wire.
On applying right-hand thumb rule, we find the direction of magnetic field. The field is in the form of concentric circles centred on the wire carrying current.
Hence, the option (d) is correct.

According to Fleming's Left Hand rule, the direction of force is perpendicular to the direction of magnetic field and current. Here, since the direction of current is taken opposite to the direction of motion of electrons, the force is directed into the page. 

The correct answers are (c) and (d). Each moving charged particle in a magnetic field experiences a force. The direction of force experienced by a positive charge (i.e., a proton) is given by Fleming's left hand rule. The force acting on the proton would change both velocity and momentum.