- Diagram 4.1 shows a cell connected in series with a
bulb, an ammeter and a switch. A high resistance voltmeter connected
across the cell gives a reading of 2 V when the switch is open (OFF) and a reading of 1.5 V when the switch
is closed (ON). The reading on the ammeter when the switch is closed (ON)
is 0.3A.
Rajah
4.1 menunjukkan satu bateri disambung secara siri dengan satu mentol, satu
ammeter dan satu suis. Satu voltmeter berintangan tinggi disambung merentasi
bateri memberi bacaan 2V bila swis
dimatikan dan bacaan 1.5V apabila swis
dihidupkan. Bacaan ammeter bila suis dihidupkan ialah 0.3A.
(a) What is the emf of
the cell?
Berapakah emf bateri itu?
………………………………………………………………………….
[1 mark] / [1 markah]
(a)
What causes the difference in the voltmeter reading
when the switch is ON and when the switch is OFF?
Apakah yang menyebabkan
perbezaan bacaan voltmeter bila suis dihidupkan dengan bila suis dimatikan?
………………………………………………………………………….
[1 mark] / [1 markah]
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|
(i) resistance of the bulb
|
4 (b)
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[2 marks] / [2 markah]
(ii) the
internal resistance of the cell.
Rintangan dalam bateri.
[2 marks] / [2 markah]
(d)
Another identical bulb is added in parallel with the
existing bulb. What is the reading of the voltmeter when the switch is ON.
Satu mentol yang serupa ditambah selari dengan
mentol sedia ada. Apakah bacaan voltmeter apabila suis dihidupkan.
[1mark]
/ [1 markah]
2 V
Internal resistance//
R = V/I
= 1.5/0.3
=5 Ω
r = E-V
I
=2.0-1.5
0.3
=1.67Ω
=E/(R+r)
= 2.0/(2.5+1.67)
=0.5 A