# E.M.F And Internal Resistance Flashcards Preview

## Physics - Topic 3 - Electric Circuits > E.M.F And Internal Resistance > Flashcards

Flashcards in E.M.F And Internal Resistance Deck (36)
1
Q

[………] have an Internal Resistance.

A

Batteries

2
Q

Resistance in metals comes from electrons colliding with 1-[………] and 2-[………] energy

A

1-Atoms (or ions)

2-losing

3
Q

In a battery what kind of energy does it use to make electrons move?

A

Chemical energy

4
Q

What is Internal Resistance?

A

Is when electrons collide with atoms inside the battery creating a resistance

5
Q

Internal resistance is what makes batteries and cells [……..][….] when they are used.

A

Warm up

6
Q

We assume wires have […….] resistance.

A

Zero

7
Q

A

Is the total resistance of all the components in the external circuit, can also be called ‘external resistance’

8
Q

How does a battery produce energy?

A

By chemical reactions

9
Q

What is the Electromotive force or E.M.F?

A

The total amount of work the battery does on each coulomb of charge.

10
Q

What is E.M.F measured in?

A

Volts

11
Q

What is the E.M.F equation?

A

ε = W / Q

12
Q

ε = W / Q What is W?

A

Is the work done on the charge.

13
Q

What is the Potential Difference across the load resistance?

A

Is the work done when one coulomb of charge flows through the load resistance. Is called the ‘terminal P.D’

14
Q

What would the the Terminal P.D equal if there was no internal resistance?

A

Terminal P.D would be the same as the E.M.F

15
Q

What is the energy that is waged by overcoming the internal resistance called?

A

Lost Volts

16
Q

What is Lost Volts?

A

The energy water per coulomb overcoming the internal resistance

17
Q

How does the conservation of energy law apply to Internal Resistance?

A

Energy per coulomb supplied by the source = energy per coulomb used in load resistance + energy per coulomb wasted in internal resistance

18
Q

List 4 different E.M.F equations.

A
```ε = V + v
ε = I(R + r)
V = ε - v
ε = V + Ir```
19
Q

What does ε stand for?

A

E.M.F

20
Q

What does V stand for?

A

Terminal P.D ( the p.d across the load resistance)

21
Q

What does v ( little v ) stand for?

A

Lost volts

22
Q

What does I stand for?

A

Current

23
Q

What does R stand for?

A

24
Q

What does r stand for?

A

Internal resistance ( resistance inside the battery )

25
Q

How do you calculate E.M.F (ε) for multiple cells in series?

A

ε(Total) = ε(1) + ε(2) + ε(3)

26
Q

How do you calculate the E.M.F for multiple IDENTICAL cells in Parallel?

A

ε(Total) = ε(1) = ε(2) = ε(3)

The total E.M.F of the combination of cells is the same size as the E.M.F of each of he individual cells

27
Q

What is the independent variable?

A

The variable you change

28
Q

What is the dependant variable?

A

Is the variable you measure

29
Q

What is the control variable?

A

Is the variable you do not change

30
Q

When investigating Internal Resistance and E.M.F what do we measure?

A

The P.D for servers different values of current

- Bart the current by changing the value of the load resistance with the variable resistor

31
Q

When investigating Internal Resistance, what kind of graph do we plot?

A

P.D (y axis)

Current (x axis)

32
Q

When measuring Internal Resistance and E.M.F what equation do we rearrange?

A

ε = V + Ir

33
Q

When investigating Internal Resistance and E.M.F - what do we rearrange ε = V + Ir to give?

A

V = -rI + ε

34
Q

When investigating Internal Resistance and E.M.F, what part of V = -rI + ε are constants?

A

ε & r

35
Q

When investigating the Internal Resistance and E.M.F, what does the y-intercept equal on a P.D (y axis) to Current (x axis)?

A

Y-intercept = ε

36
Q

When investigating Internal Resistance and E.M.F, what does the gradient on a P.D (y axis) to Current (x axis) equal?

A