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Ohmโs Law โ Find R ๐ฎ๐
I = V / R. Vary supply voltage, measure current, fit slope to estimate R. Bulb glows with P = VI; ammeter needle fluctuates.
SS2 โข Electricity โ
Circuit: Battery โ
Switch
โ
Ammeter
โ
Bulb (unknown R)
โ Battery
OFF
Ammeter (0โ2.5 A)
0.000
A
Supply Voltage
0.0 V
Measured Current
0.000 A
Power (P = VI)
0.00 W
Fuse: OK
Tiny measurement noise added (ยฑ0.5% + ยฑ0.002 A). Switch ON to energize circuit. Fuse trips above ~12 W.
Voltage V (manual)
โ0.5
+0.5
Use slider or buttons.
Auto-step sequence
๐ Sweep 0โ12 V (step 1V)
Switch must be ON. Fuse may trip at high power.
๐ธ Measure (add VโI)
๐ Compute R from fit
โป๏ธ Reset
Hidden true R (ฮฉ):
โ hidden โ
(Revealed after compute)
Your estimate R (ฮฉ):
โ
Switch ON and collect 5โ8 points โญ
VโI Readings ๐
#
V (V)
I (A)
P (W)
Graph: Current I (A) vs Voltage V (V) ๐
Best-fit line through origin: I = (1/R)ยทV
Quick Theory ๐ง
Ohmโs law:
V = IR
. Plot
I
vs
V
, slope =
1/R
. So
R = 1/slope
for a line through the origin.