Page 32 - 6413

3. Choose such resistance R at the resistance box when the
0
balance of the bridge is determined (the galvanometer indicates zero).
4. Increase the electric current by rheostat, switch on "precision"

and set the bridge in balance due to the slidewire at the resistance box.
5. Fill in the table with the experimental data R and respectively
0
length l , l for the first resistor R .
1 2 X 1
6. Carry out similar measurements for another resistors R and
X 2
R .
X 3
7. Connect three resistors in parallel and carry out measurements.
8. Connect three resistors in series and carry out similar

measurements.
9. Use to work formula:
l
R  R  1
X 0
l
2
resistor l 1 l 1 l 2 l 2 R 0 R R X R
0
X
R X1
R X2
R X3

parallel
series

10. The formula for calculating indirect measurement errors:

 R  R l  l 
  x  0  1  2
R R l l
x 0 1 2

3. Test questions
1. Ohm’s law. Resistance. Unit of resistance.

2. Specific resistance.
3. Resistance in series.
4. Resistance in parallel.

5. Kirchhoff's first rule (Kirchhoff's junction rule).
6. Kirchhoff's second rule (Kirchhoff's loop rule).
7. Wheatstone bridge.

31