# PHYSICS - ISA

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How do you calcuate the percentage uncertainty?
1 of 25
To what sig. fig. do you place the percentage uncertainty?
2 sig. fig.
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State the precision of the instruments used.
+/- 0.01 A/V
3 of 25
Why do you think you could be instructed to switch off or disconnect the cell between readings?
To prevent the cell overheaiting or running down
4 of 25
What is the difference between a systematic error and a random error?
SYSTEMATIC: part of the experiment, predictable, occurs each time you measure. RANDOM: external source causes problems, no way of predicting, will only occur sometimes.
5 of 25
How do you calculate the percentage uncertainty in your largest mean current reading?
Uncertainty= Haf the range/Mean (+/- 0.5) x Spread of results
6 of 25
If a resistor R came into contact with the connecting clips or pugs, how would that effect the values of current I?
The current would fall
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State and explain the type of error introduced by contact resistance.
Systematic error because it is a faut withing the equipment. Everytime contact is made, the resistance is the same
8 of 25
When assessing the reliability of your experiment, what do you talk about?
Either the spread of repeats, or the closeness to the line of best fit
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How do you work out the gradient of the graph?
Y axis / X axis
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What does Y=Mx+C represent?
The equation of a straight line
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How do you rearrange Y=Mx+C for the ISA?
Y=C+Mx
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How does changing the temperature 10'C effect the percentage of the resistance of the wire?
Every 10'C changes 5%
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State the list of 8 things you must remember when answering Q.4.
(1) IV/DV (2) Equipment (diagram) (3) No' of readings (min. 7) (4) Repeats (5) Show of findings (graph, 3x, cac. average) (6) Linear/Directy Proportional? (7) Reduce Uncertainty (disconnect the cell after each reading) (8) Safety
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What is meant by the term reliabilty?
Repeatable results that will follow the general pattern. Also when repeated, the results will be the same or similar.
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How can you make your resuts more reliable?
Repeating the experiment and getting the same results
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Name two ways of identifying if results are unreliable.
The repeats widely vary and there is no pattern seen in results
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What is meant by the term precision?
How small a measurement is.
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what is meant by the term accuracy?
How close the results are to the true value
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What is a continuous variable? What type of graph should be used for this type of date?
A variable that can have any numerical value. A line graph should be used to represent this data
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What is a categoric variable? What type of graph should be used to represent this data?
A variable that is described by a abel. A bar chart should be used to represent this
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How can you ensure validity? Why?
By keeping a fair test to be able to draw a valid conclusion from the results
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Why do you need to control variables?
To ensure the only factor effecting the dependant is the independant
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Name three factors that can't be controlled.
(1) Humidity/Drafts (2) Air Movements (3) Temperature changes in the room
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What is a fair test?
A fair test is a test which the IV is allowed to affect the DV. This means only changing the IV and controlling the other factors and variables to keep the same
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## Other cards in this set

### Card 2

#### Front

To what sig. fig. do you place the percentage uncertainty?

2 sig. fig.

### Card 3

#### Front

State the precision of the instruments used.

### Card 4

#### Front

Why do you think you could be instructed to switch off or disconnect the cell between readings?

### Card 5

#### Front

What is the difference between a systematic error and a random error?

#### Back

Report

is this related to the physics isa 3t which is for 2012/13??? or is it based on a past isa ?

Report

Is this what the 2012/13 physics electricity ISA questions are like ?

Report

Much of this is very wrong

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