Electricity

Front

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.

Back

An electric current is the flow of electrons in a circuit.

Front

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.

Back

The electrons are not able to move about freely.

Front

Which of the following substances is the best conductor of electricity?

Glass

,

Wood

,

Water

,

Mercury

Back

Mercury

Front

SI unit for electric current? Options: Ohm, Watt, Ampere, Volt

Back

Ampere

Front

Why is nichrome used instead of copper in electric kettles?

Back

Nichrome has higher resistance than copper, so more heat can be generated.

Front

Material used in a light bulb to produce heat and light: Nichrome, Copper, Tungsten, Steel

Back

Tungsten

Front

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

Back

Electric kettle

Front

A higher resistance in a circuit causes a _____________. Options: higher voltage, larger current, smaller current, lower voltage.

Back

smaller current

Front

Which of the following is not a source of electrical energy?

• ammeter
• dry cell
• mains
• dynamo

Back

ammeter

Front

The instrument that measures electric current is called ___________.

Back

an ammeter