• We need your support!

    We are currently struggling to cover the operational costs of Xtremepapers, as a result we might have to shut this website down. Please donate if we have helped you and help make a difference in other students' lives!
    Click here to Donate Now (View Announcement)

Physics, Chemistry and Biology: Post your doubts here!

H

Heba A.Moety

Messages
110
Reaction score
136
Points
53
Heba A.Moety said:
Centre of mass experiment (with the lamina): How to minimize inaccuracy when marking the lines : you view the string directly in front of card.

Why angle i is NOT equale to angle r in ray experiment:

- thickness of pins
-thickness of mirror
-protractor is not precise

In an experiment to do with the cooling of water, there are certain things which must be kept the same:

- initial temp.
-thickness of test-tubes ( more heat lost when thinner etc.)
-vol. of water
-thickness of cotton wool
-depth of the thermometer in the water
-avoid droughts


Examples of insulators that you can wrap things with:
-bubble wrap
-fiberglass
Styrofoam is a good insulator , however you cannot wrap it around things as it breaks easily.

inaccuracy of ray box method: thickness of rays.
inaccuracy of pin method: pins not straight, or too close, or thickness of lines drawn.

Symbol for extension is 'x' or 'e'.

A ruler is called a 'rule'.

ALWAYS ROUND TO 3.SIG.FIGS.

To improve accuracy, put pins in the light ray experiment FURTHER APART to avoid parallax error. So, I I I is better than I I I (where I is the pins)

Precautions for circuit readings of I and V so that accurate:

For I specifically :
-limit current so that temp. doesn't increase
-use a tapping meter

For I and V: Switch off between readings.

θ this is the symbol for Celsius temp. (theta)
T this is the symbol for Kelvin temp.

In light ray experiment, lengths are in mm.


Fair test for pendelum experiments:
-length of pendelum
-shape of bob
-no. of swings
-amplitude

If a statement is 'directly proportional', the justification would always be , ''straight line that goes through the origin''.

If you're comparing the extensions of springs of different materials, certain things have to be the same:
-the cross-section of the springs
-the length of the springs
-no. of coils
-range of loads
-length of wire

How to reduce the heating effect of current:

-Add a variable resistor
-reduce current
-reduce voltage or power
-switch off between readings

Precautions for focal length experiments:
-do it in a darkened room
-clamp ruler to bench
-avoid parallax error when reading the lengths
-make sure that the obejct/lense/screen are all perpendicular to bench.
-and of course, repeats.

A question one came up and asked to draw a diagram of a load on a ruler on a pivot. Well, this meant that the ruler was unbalanced, and so this means that when you draw it, you must show that the ruler is tilted.

DON'T FORGET TO WRITE DOWN THE UNITS AFTER EACH ANSWER!!

An important precaution for spring experiments is to wait for the spring to stop moving and then record the length.

source: balloonsandhighlighters
Click to expand...
 
R

roselmoreno21

Messages
23
Reaction score
43
Points
23
anyone has something about colour flames and colour when water is added of elements?? (chemistry help please!!!)
thankyouuuu!!
 
You must log in or register to reply here.
Top