An ammeter is calibrated such that a positive deflection of its pointer is obtained when current enters the instrument at its marked ‘+’ terminal. A student accidentally connects the ammeter in a circuit so that current enters at the ‘–’ terminal and leaves at the ‘+’ terminal.
(a) Predict the behaviour of the ammeter pointer when the circuit is switched on. Give reasons for your answer with reference to the nature of conventional current.
(b) Explain, with reference to electron motion, what actually happens inside the ammeter coil during this reverse connection.
(c) The same student claims that reversing the physical direction of electron flow must change the amount of heat produced in the circuit resistor. Analyse this claim and justify whether it is correct or incorrect.