Question

Draw a diagram to show the pattern of magnetic field lines on a horizontal sheet of paper due to a straight conductor passing through its centre and carrying current vertically upwards. Mark on it (i) the direction of current in the conductor and (ii) the corresponding magnetic field lines. State right hand thumb rule and check whether the directions marked by you are in accordance with this rule or not.

Ravi performed an experiment in his school laboratory to study the magnetic effect of electric current. He passed electric current through a straight copper conductor placed near a magnetic compass. He observed that the compass needle deflected when current flowed through the conductor. When the direction of current was reversed, the direction of deflection of the compass needle also reversed. Later, Ravi used a solenoid connected to a battery and placed a soft iron core inside it. He observed that the solenoid behaved like a bar magnet when current flowed through it and lost its magnetism when the current was switched off.

An electron enters a magnetic field at right angles to it, as shown in Fig. 12.14. The direction of force acting on the electron will be

A positively-charged particle (alpha-particle) projected towards west is deflected towards north by a magnetic field. The direction of magnetic field is