9702/Oct Nov/11/2015/Q4

A calibration graph is shown for an ammeter whose scale is inaccurate.

Two readings taken on the meter at different times during an experiment are 0.13 mA and
0.47 mA.

By how much did the current really increase between taking the two readings?

A 0.30 mA
B 0.35 mA
C 0.40 mA
D 0.44 mA

Solution:
Answer: A

When ammeter reading = 0.13mA, the current = 0.14mA
When ammeter reading = 0.47mA, the current = 0.44mA
The current increase between taking the two reading is 0.44mA - 0.14mA = 0.3mA

Reference: PYQ - Oct/Nov 2015 Paper 11 Q4