Magnetic Effects of
Electric Current
13
EXERCISE 13.1
Topics:
Magnetic field and field lines
Magnetic field due to a current carrying conductor
Right hand thumb rule
Magnetic field due to a current through a circular loop
Solenoid
1 MARK
1.
Name the two factors that completely define a magnetic field at a point.
(2014)
Ans. Magnetic field is a quantity that has both direction and magnitude.
2.
State the direction of the magnetic field inside the bar magnet?
(2014)
(2014)
Ans. From South pole to North pole.
3.
List two sources of magnetic fields.
Ans. 1. Magnet
4.
2. Electromagnet
State the observation made by Oersted on the basis of his experiment with current
carrying conductors ? (2013, 2014)
Ans. Every current carrying conductor has a magnetic field around it.
6.
State the effect on the strength of magnetic field produced at a point near a straight
conductor if the electric current flowing through it increases. (2013)
Ans. The strength of the magnetic field increases.
7.
Suggest one way of discriminating a wire carrying current from a wire carrying no
current. (2013)
Ans. Bring a magnetic needle near the wire. A current carrying wire will produce a deflection
in the needle whereas a wire without current will not.
TEACHERS FORUM
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Science Question Bank SA - 1 - CBSE (CCE)
8. Name the physical quantities which are indicated by the direction of thumb and
forefinger in the Fleming’s right hand rule ? (2011, 2012)
Ans. Direction of motion of the conductor and direction of field respectively.
2 MARKS
9. How does the strength of the Magnetic field at the centre of a circular coil of a wire
depend on : (a) radius of the coil (b) number of turns in the coil.
(2012)
Ans. (a) As radius increases magnetic field decreases.
(b) Magnetic field produced is directly proportional to the number of turns in the coil.
10. Why are the magnetic field lines closed curves?
(2013)
Ans.It is taken by convention that field lines emerge from North pole and merge at the
South Pole. Inside the magnet, the direction of field lines is from S pole till N Pole,
thus magnetic field lines are closed curves.
11. Identify the poles of the magnet in the given figure (1) and (2).
(2012)
Ans.
12.
Magnetic field lines are shown in the given diagram. A student makes a statement
that magnetic field at X is stronger than at Y. Justify this statement. Also redraw the
diagram and mark the direction of magnetic field lines.
(2010)
Ans.The relative strength of the magnetic field is shown by the degree of closeness of the
field lines. The degree of closeness is more at ’X’ than at ‘Y’. Therfore field is stronger
at ‘X’ where the field lines are crowded.
Direction of magnetic field is from North pole to south pole.
TEACHERS FORUM
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