NCERT Class X Science Class: Chapter –13. Magnetic Effects of Electric Current – Part-1

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Multiple Choice Questions

Question 1:

Choose the incorrect statement from the following regarding magnetic lines of field

(a) The direction of magnetic field at a point is taken to be the direction in which the north pole of a magnetic compass needle points

(b) Magnetic field lines are closed curves

(c) If magnetic field lines are parallel and equidistant, they represent zero field strength

(d) Relative strength of magnetic field is shown by the degree of closeness of the field lines

Answer: C

Image Magnetic field lines are parallel and equidistant

Image Magnetic Field Lines Are Parallel and Equidistant

Image Magnetic field lines are parallel and equidistant

Question 2:

If the key in the arrangement (Figure) is taken out (the circuit is made open) and magnetic field lines are drawn over the horizontal plane ABCD, the lines are

Image of Variable Resistance

Image of Variable Resistance

Image of Variable Resistance

(a) Concentric circles

(b) Elliptical in shape

(c) Straight lines parallel to each other

(d) Concentric circles near the point O but of elliptical shapes as we go away from it

Answer: C

Only earth’s magnetic field will be present

Image Earth’s magnetic field

Image Earth’S Magnetic Field

Image Earth’s magnetic field

Question 3:

A circular loop placed in a plane perpendicular to the plane of paper carries a current when the key is ON.The current as seen from points A and B (in the plane of paper and on the axis of the coil) is anti-clockwise and clockwise respectively. The magnetic field lines point from B to A. The N-pole of the resultant magnet is on the face close to

Image Variable Resistance

Image Variable Resistance

Image Variable Resistance

(a) A

(b) B

(c) A if the current is small, and B if the current is large

(d) B if the current is small and A if the current is large

Answer: A

Misconception is that magnetic field lines point from north to South Pole. The fact is that they emerge out of North Poleand entre into South Pole.

Image Magnetic field lines point from North to South Pole

Image Magnetic Field Lines Point from North to South Pole

Image Magnetic field lines point from North to South Pole

Question 4:

For a current in a long straight solenoid N- and S-poles are createdat the two ends. Among the following statements, the incorrect statement is

(a) The field lines inside the solenoid are in the form of straight lines which indicates that the magnetic field is the same at all points inside the solenoid

(b) The strong magnetic field produced inside the solenoid can be used to magnetise a piece of magnetic material like soft iron, when placed inside the coil

(c) The pattern of the magnetic field associated with the solenoid is different from the pattern of the magnetic field around a bar magnet

(d) The N- and S-poles exchange position when the direction of current through the solenoid is reversed

Answer: C

Image Solenoid and Bar Magnet

Image Solenoid and Bar Magnet

Image Solenoid and Bar Magnet

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