NCERT Class X Science Class: Chapter –13. Magnetic Effects of Electric Current – Part-3

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Question 9:

A constant current flows in a horizontal wire in the plane of the paper from east to west as shown in Figure. The direction of magnetic field at a point will be North to South

Image North to south point

Image North to South Point

Image North to south point

(a) Directly above the wire

(b) Directly below the wire

(c) At a point located in the plane of the paper, on the north side of the wire

(d) At a point located in the plane of the paper, on the south side of the wire

Answer: B

Question 10:

The strength of magnetic field inside a long current carrying straight solenoid is

(a) More at the ends than at the center

(b) Minimum in the middle

(c) Same at all points

(d) Found to increase from one end to the other

Answer: C

Image The strength of magnetic field

Image the Strength of Magnetic Field

Image The strength of magnetic field

Question 11:

To convert an AC generator into DC generator

(a) Split-ring type commutator must be used

(b) Slip rings and brushes must be used

(c) A stronger magnetic field has to be used

(d) A rectangular wire loop has to be used

Answer: A

DC- split ring commuttator AC-2 rings

DC- Split Ring Commuttator AC-2 Rings

DC- split ring commuttator AC-2 rings

Question 12:

The most important safety method used for protecting home appliances from short circuiting or overloading is

(a) Earthling

(b) Use of fuse

(c) Use of stabilizers

(d) Use of electric meter

Answer: B

Image Use of fuse - most important safety method

Image Use of Fuse - Most Important Safety Method

Image Use of fuse - most important safety method

Short Answer Questions

Question 13:

A magnetic compass needle is placed in the plane of paper near point A as shown in Figure. In which plane should a straight current carrying conductor be placed so that it passes through A and there is no change in the deflection of the compass? Under what condition is the deflection maximum and why?

Image Magnetic compass

Image Magnetic Compass

Image Magnetic compass

Answer:

The straight current carrying conductor should be placed in the plane of paper so that it passes through A. This produces magnetic field in a plane perpendicular to plane of paper.

The compass needle remains undetected due to vertical magnetic field produced by wire since compass needle are free to rotate only in horizontal plane. The deflection in compass needle is maximum when the conductor through A is perpendicular to the plane of paper and the magnetic field due to straight current conductor lies in the plane of paper.