Fill in the blank: An electromagnet consists of a coil of wire wrapped around a ___ core.

Soft iron

Explain how the polarity of an electromagnet can be changed.

The polarity of an electromagnet can be changed by reversing the direction of the electric current flowing through the coil.

True or False: The Earth's magnetic field is generated by the movement of solid iron in its core.

False: Its generated by the movement of liquid iron in its core.

What are lifting electromagnets and where are they commonly used?

Lifting electromagnets are common tools.

• Used for lifting heavy metals.

• Common in scrap yards.

• Essential for factory operations.

Riddle: I can heat your home, cook your food, and even dry your hair. What am I?

An electric appliance.

What happens to a conductor when electric current flows through it?

Conductors heat up with current.

• Resistance causes energy loss.

• Heat generation can damage components.

• Applications include heating elements.

Fill in the blank: A dry cell is called 'dry' because its electrolyte is a ___ paste.

Moist

Describe the process of making a simple electric cell using a lemon.

Insert copper and iron in lemon juice.

• Lemon juice serves as electrolyte.

• Copper and iron create reaction.

• Generates small amount of electricity.

What is resistance in the context of electric current?

Resistance is the property of a material that opposes the flow of electric current, causing energy to be converted into heat.

Multiple Choice: Which of the following increases the strength of an electromagnet? 
A) Decreasing the number of wire turns 
B) Using a thicker wire 
C) Increasing the current
D) Removing the iron core

C) Increasing the current

True or False: Rechargeable batteries can be used only once before being discarded.

False. Rechargeable batteries can be recharged and used multiple times.

Fill in the blank: The warming up of a conductor due to the passage of electric current is called the ___ effect of electric current.

Heating

Explain the role of electrodes in an electric cell.

Electrodes are crucial in electric cells.

• Conduct electricity from reactions.

• Serve as terminals for current.

• Facilitate chemical energy conversion.

What is the magnetic effect of an electric current?

The magnetic effect of an electric current is the phenomenon where electric current flowing through a conductor produces a magnetic field around it.