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.

Tags

NGSS.MS-PS1-4

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

Tags

NGSS.MS-PS2-3

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