This document discusses solenoids and how to determine the magnetic field around them. It explains that a solenoid is a coil of wire that produces a magnetic field similar to a bar magnet when electric current flows through it. The right hand rule is used to determine the north and south poles of a solenoid by placing the hand at the positive end and orienting the thumb to point north. Examples are given to demonstrate how to apply the right hand rule to identify pole orientation in different solenoid setups.

1. SOLENOIDS
Objectives:
2.3 Map the magnetic field around a
current bearing:
a) straight line conductor
b) solenoid

2. Solenoid
 Wire wrapped in a coil with a current
flowing
 Makes a magnetic field
 Their magnetic fields look like the
magnetic field around a bar magnet.

3. Cores
 A Core is the object that is inserted into
the solenoid, creating an electromagnet.
 Different materials influence the strength
of the electromagnet: Iron, Nickel or
Cobalt.
 Iron is used because when you turn off
the electricity it demagnetizes.
 REMANENCE: Steel is not used because it
remains magnetized.

4. Right Hand Rule 1
 Given a solenoid, this method
determines the polarity.

5. Solenoid Rules – Right Hand Rule
 Step 1: Place right hand palm on
positive end.
Finding
North & South
Poles
- +

6. Solenoid Rules – Right Hand Rule
 Step 2: At the + end, see if the
wire is in front or behind the tube.
Wire is in
Front of the core
At positive end.
+
-

7.  Step 3: Wire on top  Hand on top.
Solenoid Rules – Right Hand Rule
- +

8.  Step 4. Wire under  Hand under.
Solenoid Rules – Right Hand Rule
- +
Palm Up
Hand under tube

9.  Step 5. Thumb = North.
Solenoid Rules – Right Hand Rule
- +

10. Solenoid Examples - # 1
1. Go to the
positive
2. Wire runs behind
core
3. Hand goes under
core & fingers
curl up
4. Thumb points N.
Other end is S.
5. Lines of Magnetic
force run N
(Nerd) to S
(Sexy).
+
-

11. Solenoid Example # 2
1. Find Positive
2. Wire runs in
front of core
3. Place hand on
positive
4. Thumb points
to North
5. Other end is S
6. Magnetic field
runs N (Nerd)
to S (Sexy).
-
+

12. Solenoid Example # 2
1. Find Positive
2. Wire runs in
front of core
3. Place hand on
positive
4. Thumb points
to North
5. Other end is S
6. Magnetic field
runs N (Nerd)
to S (Sexy).
-
+

13. Activities
 Work Sheet Mod II, # 3
 Gizmo - Magnetism

14. Effects of Placing a Compass Near a
Solenoid
1. Label North and South.
2. Draw in arrow on compass.
Example #1
- +
Compass
Remember
That the
Needle is
North
Needle points
to
South

15. More Examples
1. Label North and
South.
2. Draw in arrow on
compass.
Example #2
-
+
Compass

16. When Two Solenoids Meet
 Answer: Solenoids would attract.
Would they attract or repel?
+ -
- +
Likes
Repel &
Opposites
Attract

17. Solenoid without a + or -
In a battery
the longer line is
ALWAYS
positive
First
Find the
positive
+ -

18.  Right Hand Rule: Use only the right
hand to label N and S.
 Before solving a problem, always label
N and S first.
 Red Compass needle is North and
is attracted to South.
 When the + and the – are not given
on a diagram, the longer line on the
battery is always positive.

19.  Given a live conductor with electricity,
this method determines the polarity of
the magnetic field around it.
Right Hand Rule 2
Straight Line Conductor

20.  Step 1: Using your right hand,
point your thumb towards the
NEGATIVE POST.
Straight Line Conductor
Right Hand Rule
- +
Hand on top
in this
situation

21.  Step 2: With your hand open, your
kNuckles are North; your
finger tipS are South.
Straight Line Conductor
Right Hand Rule
+
-

22. Straight Line Conductor
Right Hand Rule
If your hand is
behind the wire,
curl your hand
around the
wire.
-
+
-
+
kNuckles are
up (N)
finger tipS are
down (S)

23. Placing N & S –
Straight Line Conductor
+
+
+
+
-
-
-
-

24. Effects of a Straight Line Conductor
on a Compass
- +
Compass arrow
Always points
South
Compass

25. Armour Rule:
 For a straight line conductor
connected to a source of electricity,
the finger tips of the right hand
point in the North direction of the
compass.

26. Straight Line Conductor
Examples
-
-
-
- +
+
+
+
A B
C D

27.  Right Hand Rule for Straight Line
Conductors – Thumb points to
negative
 North and South are never on the
ends of the line
 Remember that the compass needle
is North and is attracted to South
 kNuckles are North and finger tipS
are South.

28. Activity
 Worksheet Module 2, # 5
 Page 174, Q. 21-25

29. Important Symbols & Facts
 Magnetic field: represented by B.
 Current: represented by I.
 Magnetic Poles:
 North pole (N)
 South Pole: (S)
 Magnetic Field: Circular around a
straight line.