Chapter 12 · Magnetic Effects of Electric Current

NCERT Class 10 Science Chapter 12 Intext Questions (Page 201)

All 3 questions of NCERT Class 10 Science Chapter 12 Intext Questions (Page 201) — Magnetic Effects of Electric Current — in the book's order, each with its answer and a step-by-step solution.

1. Q1
   Consider a circular ​loop of wire ​lying in the plane of ​the table. Let ​the current pass through the loop clockwise. Apply the ​right-hand rule to find ​out ​the direction of the magnetic field inside ​and outside the loop.
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   Inside the loop the field is downwards, into the table; outside it is upwards, out of the table.

   Inside the loop the magnetic field is directed vertically downwards, that is into the table, at right angles to the plane of the loop. Outside the loop the field is directed vertically upwards, out of the table. Curling the fingers of the right hand along the clockwise current gives a thumb pointing down through the loop, and because field lines are closed curves the lines that go down through the loop return upwards all around the outside. The upper face of the loop therefore behaves as a south pole and the lower face as a north pole.

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2. Q2
   The ​magnetic ​field in a given region is ​uniform. ​Draw a diagram ​to represent it.
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   A uniform field is drawn as straight, parallel, equally spaced lines with arrowheads all in the same direction.

   A uniform magnetic field is represented by straight, parallel field lines that are equally spaced and all carry arrowheads pointing the same way, drawn right across the region. The parallel arrows say that the direction is the same at every point, and the equal spacing says that the magnitude is the same at every point. If the field is at right angles to the plane of the paper it is drawn instead as an evenly spaced array of crosses (field going into the page) or of dots (field coming out of the page). The field inside a long current-carrying solenoid is the standard example. The figure shows both forms of the diagram.

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3. Q3
   Choose the correct option. The ​magnetic ​field ​inside ​a long ​straight solenoid-carrying ​current

   1. (a)is zero.
   2. (b)decreases as we move towards its end.
   3. (c)increases as we move towards its end.
   4. (d)is the same at all points.
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   (d) is the same at all points.

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