Chapter 11 Electricity

NCERT Class 10th

Science SOLUTIONS

Subject
Question

Why does the cord of an electric heater not glow while the heating element does?

Updated on May 31, 2025 | By Learnzy Admin | 👁️ Views: 123 students

Solution
✔ Verified

The cord of an electric heater does not glow because it is made of a material with low resistance, so it does not heat up much.

The heating element glows because it is made of a material with high resistance, which causes it to get very hot and produce light when current passes through it.

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More Questions on Electricity

Question 1

What determines the rate at which energy is delivered by a current?


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Question 2

An electric iron of resistance 20 Ω takes a current of 5 A. Calculate the heat developed in 30 s.


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Question 3

Compute the heat generated while transferring 96000 coulomb of charge in one hour through a potential difference of 50 V


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Question 4

What are the advantages of connecting electrical devices in parallel with the battery instead of connecting them in series?


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Question 5

Why are coils of electric toasters and electric irons made of an alloy rather than a pure metal?


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Question 6

Let the resistance of an electrical component remains constant while the potential difference across the two ends of the component decreases to half of its former value. What change will occur in the current through it?


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Question 7

Will current flow more easily through a thick wire or a thin wire of the same material, when connected to the same source? Why?


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Question 8

On what factors does the resistance of a conductor depend?


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Question 9

What is meant by saying that the potential difference between two points is 1 V?


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Question 10

Name a device that helps to maintain a potential difference across a conductor.


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Question 11

Calculate the number of electrons constituting one coulomb of charge.


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Question 12

Define the unit of current.


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Question 13

What does an electric circuit mean?


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Question 14

How much energy is given to each coulomb of charge passing through a 6 V battery?


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Question 15

What is the maximum resistance which can be made using five resistors each of 1/5 Ω ?


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Question 16

A current of 1 A is drawn by a filament of an electric bulb. Number of electrons passing through a cross section of the filament in 16 seconds would be roughly.


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Question 17

Calculate the resistivity of the material of a wire of length 1 m, radius 0.01 cm and resistance 20 ohms.


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Question 18

List the factors on which the resistance of a conductor in the shape of a wire depends.


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Question 19

Why are alloys commonly used in electrical heating devices ?


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Question 20

Why are metals good conductors of electricity whereas glass is a bad conductor of electricity ? Give reason.


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Question 21

Calculate the resistance of a metal wire of length 2 meters and cross-sectional area 1.55 × 10⁻⁶ square meters, if the resistivity of the metal is 2.8 × 10⁻⁸ ohm meter.


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Question 22

How is the resistivity of alloys compared with those of pure metals from which they may have been formed?


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Question 23

Name a device that you can use to maintain a potential difference between the ends of a conductor. Explain the process by which this device does so.


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