# 6-4 Bodily resistance and resistance in series (6.2)

Bodily resistance and resistance in series (p 228)

Stationary
- Writingbook
- Pen and pencil
- Calculator

Mark
- NO

Lessonup
- YES
schoolbag in
the cupboard
Phones in the phonebag
1 / 26
Slide 1: Tekstslide
NatuurkundeMiddelbare schoolhavoLeerjaar 3

In deze les zitten 26 slides, met interactieve quizzen en tekstslides.

Lesduur is: 50 min

## Onderdelen in deze les

Bodily resistance and resistance in series (p 228)

Stationary
- Writingbook
- Pen and pencil
- Calculator

Mark
- NO

Lessonup
- YES
schoolbag in
the cupboard
Phones in the phonebag

#### Slide 1 -Tekstslide

Lesson goals:
- Explain how bodily resistance
influences the current through
your body during an electric shock.
- Make calculations with the current,
voltage and resistance in a series circuit.

#### Slide 2 -Tekstslide

Size of the current?
- Depends on the voltage and
resistance.
- Total bodily resistace =
contact resistance + body resistance

#### Slide 3 -Tekstslide

Body as a conductor
- The body is a good conductor
- Body resistance is between 100 and 500 ohm
- Contact resistance is about 100 k ohm if your skin is dry
- With a wet skin - drops to 1 000 ohm

#### Slide 4 -Tekstslide

Correct voltage for the perfect lightbulb
A lightbulb that works perfectly
at 6V could be damaged at 9V.

Say you have a battery of 9V,
but a lightbulb of 6V, could you then still conenct the lightbulb to this battery?

#### Slide 5 -Tekstslide

6V lamp and 9V powersource
Then you have to increase the resistacne
to use the 9V battery.

BECAUSE - If the resistance increases, the current will decrease.

#### Slide 6 -Tekstslide

More resistances in series
The more resistances you connect in sereis the greater the total resistance will be. Rtot = R1 + R2 + R3

SO Rtot = 250 + 550 + 1 000 = 1 800 ohm
Total resistance

#### Slide 7 -Tekstslide

Current and voltage in a series circuit
The current in a series circuit
is the same everywhere...

.... BUT the voltage is shared
accrosst he circuit components

#### Slide 8 -Tekstslide

What if the resistance are different ...
U1=IR1
U2=IR2
U3=IR3
R1
R2
R3

#### Slide 9 -Tekstslide

What is the total resistance?
A
9
B
3
C
12
D
11

#### Slide 10 -Quizvraag

How does the
current at A1 compare to the current at A2?
DIRECTION OF CURRENT
A
A1 > A2
B
A1 = A2
C
A1 < A2
D
One could not say

#### Slide 11 -Quizvraag

What is the voltage in U2?
A
3V
B
6V
C
9V
D
12V

#### Slide 12 -Quizvraag

What is the voltage in U?
A
3V
B
6V
C
9V
D
12V

What is the
current?
A
2 A
B
3A
C
5 A
D
1,2 A

#### Slide 14 -Quizvraag

What is the current?
A
7 A
B
4 A
C
3 A
D
1,2 A

#### Slide 15 -Quizvraag

What is the
magnitude of the
unknown resistance?
A
1
B
2
C
3
D
4

#### Slide 18 -Tekstslide

Do question 27 (p 238)
timer
3:00

#### Slide 20 -Tekstslide

Do question 28 (p 238)
timer
4:00

#### Slide 22 -Tekstslide

Do question 29 (p 238)
timer
4:00

What did you
learn today?

#### Slide 25 -Woordweb

You could do Q 22 and 23 in the digital method (p 231)

This is on bodily resistance

NEXT LESSON - Parallel circuits
timer
10:00