# NCERT Class X Science Class: Chapter –13. Magnetic Effects of Electric Current – Part-4

Question 14:

Under what conditions permanent electromagnet is obtained if a current carrying solenoid is used? Support your answer with the help of a labelled circuit diagram.

(i) The magnitude of direct current through the solenoid should be large.(ii)The number of turns in the solenoid should be large and closely packed, so that a strong uniform magnetic field inside it is produced.(iii) The rod kept inside is made of a magnetic material such as steel.

Question 15:

AB is a current carrying conductor in the plane of the paper as shown in Figure. What are the directions of magnetic fields produced by it at points P and Q? Given, where will the strength of the magnetic field be larger?

Into the plane of paper at P and out of it at Q. The strength ofthe magnetic field is larger at the point located closer i.e. at Q.

Question 16:

A magnetic compass shows a deflection when placed near a current carrying wire. How will the deflection of the compass get affected if the current in the wire is increased? Support your answer with a reason.

The deflection increases. The strength of magnetic field is directly proportional to the magnitude of current passing through the straight conductor.

Question 17:

It is established that an electric current through a metallic conductor produces a magnetic field around it. Is there a similar magnetic field produced around a thin beam of moving

(i) Alpha particles,

(ii) Neutrons?

In case of movement of a charged particle the magnetic field is created around the path on which the charged particle moves.(i) Yes, a thin beam of a-particles (which are positively charged) is like straight conductor carrying current in the direction of motion.(ii) No, as neutrons carry no charge so no magnetic field would be created around its path.

Question 18:

What does the direction of thumb indicate in the right-hand thumb rule? In what way this rule is different from Fleming’s left-hand rule?

The thumb indicates the direction of current in the straight conductor held by curled fingers, whereas the Fleming’s left-handrule gives the direction of force experienced by current carrying conductor placed in an external magnetic field.

Question 19:

Meena draws magnetic field lines of field close to the axis of a current carrying circular loop. As she moves away from the center of the circular loop she observes that the lines keep on diverging. How will you explain her observation?