A 6.0V battery, a resistor of 30Ω, a key, an ammeter (ideal) and a voltmeter of resistance 10kΩ are available in the laboratory.
(a) The devices are connected correctly to measure the current through and the potential difference across the resistor.
(b) By mistake the voltmeter is inserted in series with the resistor while the ammeter is connected directly across the battery terminals.
a. (i) For arrangement (a) calculate the current that should be recorded by the ammeter.
b. (ii) For arrangement (b) calculate the current that now flows in the circuit.
c. (iii) Determine the percentage error introduced in the current measurement because of the incorrect connection.
d. (iv) State two practical precautions that a student should follow to avoid such errors while setting up the circuit.