I.S homework 1

Which of the following is/are not a constituent of the wire inside a fuse?
(1) Iron
(2) Tin
(3) Lead
A. (1) and (3) only
B. (2) and (3) only
C. (1) only
D. (2) only
We can make an electromagnet stronger by using
(1) larger current.
(2) more coil.
(3) gold instead of iron as the core.
A. (2) only
B. (1) and (2) only
C. (1) only
D. (1), (2) and (3)
The energy change in a hair dryer is:
A. Electrical energy-->heat and light
B. Electrical energy-->kinetic energy
C. Electrical energy-->magnetic energy
D. Electrical energy-->heat and kinetic energy
What is the mains voltage in Hong Kong?
A. 260 V
B. 220 V
C. 240 V
D. 200 V
Which of the following would happen if there was no electricity at home?
(1) Communication would become more difficult.
(2) More energy would be used.
(3) Cooking would become much easier.
A. (1), (2) and (3)
B. (1) and (3) only
C. (1) and (2) only
D. (1) only
What is the colour of live wire?
A. Red
B. Orange
C. Blue
D. Brown
If too many appliances are connected to one mains socket, what danger would probably occur?

A. Overloading would occur because voltage in the main loop will become dangerously high.
B. Overloading would occur because current in the main loop will become dangerously high.
C. Short circuit would occur because voltage in the main loop will become dangerously high.
D. Short circuit would occur because current in the main loop will become dangerously high.
8. Which of the following statements is/are advantage(s) of a ring circuit?
(1) If one of the sockets cannot function, others can still function well.
(2) Currents in each socket will not affect each other.
(3) The power output is higher.
A. (1) and (2) only
B. (3) only
C. (1) only
D. (1) and (3) only