Question 2
State Ohm’s Law.
(b) Figure 1 is a d.c. circuit diagram containing colour coded resistors R1 and R2.
Calculate the:
- maximum resistance of resistance R1;
- maximum resistance of resistance R2;
- maximum total resistance of the circuit;
- minimum current flowing through the circuit.
The expected responses were:
-
Ohm’s Law
It states that the current flowing through a metallic conductor is directly proportional to the p.d. applied across its ends/terminals, provided the temperature remains constant.
OR
V = IR
(b)(i) R1 max = 100Ω + 5Ω = 105 Ω
(ii) R2 max = 220 Ω + 11 Ω = 231 Ω
(iii) RT max = 105 Ω + 231 Ω = 336 Ω
(iv)
The tasks in this question required candidates to specify resistance from colour codes and understand the concept of tolerance. The Chief Examiner reported that only a few candidates responded well to the tasks.