WS 8.2 answers

II.   Fill in the blanks:

1.     What is an electric current?

Ø   In some materials, there are electrons which are free to move around randomly. These electrons are called (1) free electrons.

Ø   The free electrons in a metal wire move (2) randomly in all directions when there are no dry cells in the circuit.

Ø   The free electrons in a metal wire are ‘driven’ to flow in the (3) same direction when there is a dry cell in the circuit.

2.     Measuring electric current

Ø   An (7) ammeter is an instrument used for measuring the size of an electric current.

Ø   Electric current is measured in (8) ampere(A). Small electric currents are measured in milliamperes (mA).

Ø   We should always connect the (9) positive terminal of the ammeter towards the positive pole of the dry cell and the (10) negative terminal towards the negative pole.