Passing %:
2A = 24.1%
2C = 17.2%
2014年12月19日 星期五
2014年12月11日 星期四
2014年12月9日 星期二
Quiz 7: WS8.2 answers
Fill in the Blanks (10 marks)
1 In some materials, there are electrons
which are free to move (1) randomly in all directions.
These electrons are called (2)
free electrons.
2 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.
3 The free electrons flow from the (4) negative pole of the dry cell
to the (5) positive pole. The flow of
these free electrons forms an (6) electric
current.
4 An
(7) ammeter is an
instrument used for measuring the size of an electric current.
5 Electric current is measured in (8) ampere (A). Small electric currents
are measured in milliamperes (mA).
6 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.
Challenging
Questions (Bonus 3
marks)
1. In the
diagram below, draw wires to show how the circuit should be connected in order
to measure the electric current flowing through the circuit. Indicate the
positive (+) and negative (-) terminals of the ammeter.
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