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10 questions
Which of the following best explains an electric current?
An electric current is the flow of positive charges in a circuit.
An electric current is the flow of atoms in a circuit.
An electric current is the flow of electrons in a circuit.
An electric current is the flow of neutrons in a circuit.
Which of the following statements is correct about electrical insulators?
They do not contain any atoms.
Their protons are not allowed to move about freely.
The electrons are not able to move about freely.
They are good at conducting heat only.
Which of the following substances is the best conductor of electricity?
Glass
Wood
Water
Mercury
Which of the following is the SI unit for electric current?
Ohm
Watt
Ampere
Volt
An electric kettle is commonly used to heat up water at home. The heating element used is nichrome wire and not copper. Which of the following reasons best explains why nichrome is used instead of copper?
Nichrome conducts more current than copper, so more heat can be generated.
Nichrome has higher resistance than copper, so more heat can be generated.
Nichrome has higher voltage than copper, so more heat can be generated.
Nichrome are cheaper than copper, so it is more economical.
Which of the following materials is used in a light bulb to produce heat and light?
Nichrome
Copper
Tungsten
Steel
Which of the following electrical appliances does not make use of a variable resistor?
Volume controls in radio
Dimmers in cinemas
Speed control of a toy car
Electric kettle
A higher resistance in a circuit causes a _____________.
higher voltage
larger current
smaller current
lower voltage
Which of the following is not a source of electrical energy?
ammeter
dry cell
mains
dynamo
The instrument that measures electric current is called ___________.
a resistor
a voltmeter
an ammeter
an electrometer
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