Look at the figures given below and answer the following questions: Which one is a stronger magnet among the Fig. (i) and (ii) given above and why?

The first one is the stronger magnet because the number of the round coil is greater. The more the number of turns in the coil of the wire, the more the strength of the electromagnet is created. This is due to more resistance being provided to the current flowing through the coil.

Look at the figures given below and answer the following questions: Why do we use iron for making an electromagnet and not steel?

Iron is good for making an electromagnet because steel does not lose all its magnetism when the current is stopped and it becomes a permanent magnet. To make a permanent magnet we need to heat the metal until it reaches a high temperature.

E M B I B E

LEARNING SCIENCE>Chapter 14 - Electric Current and its Effects>Exercise>Q 2

MEDIUM

7th CBSE

IMPORTANT

Earn 100

Give two advantages of electromagnets over a permanent magnet. What type of magnet is used in an electric bell?

Important Questions on Electric Current and its Effects

HARD

7th CBSE

IMPORTANT

LEARNING SCIENCE>Chapter 14 - Electric Current and its Effects>Exercise>Q 2

Draw a labelled diagram of an electric bell.

MEDIUM

7th CBSE

IMPORTANT

LEARNING SCIENCE>Chapter 14 - Electric Current and its Effects>Exercise>Q 3

What is overloading? Why is a fuse wire necessary in a circuit? How does it work?

EASY

7th CBSE

IMPORTANT

LEARNING SCIENCE>Chapter 14 - Electric Current and its Effects>Exercise>Q 1

Why can’t we use a copper wire for making an electric fuse?

EASY

7th CBSE

IMPORTANT

LEARNING SCIENCE>Chapter 14 - Electric Current and its Effects>Exercise>Q 2

A coil suspended freely, points in some direction when no current is passed through it. Can you tell what will happen when a current is passed through it?

EASY

7th CBSE

IMPORTANT

LEARNING SCIENCE>Chapter 14 - Electric Current and its Effects>Exercise>Q 1

Why does the bulb in the circuit given alongside in figure not glow? Draw the circuit with required change.

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