A wire of given length is doubled on itself and this process is r… - Vidyadip

Question

A wire of given length is doubled on itself and this process is repeated once again. By what factor does the resistance of the wire change?

✓

Answer

As the length of the wire become $\frac{1}{4}$ of the original length its area of cross-section become 4 times.
So, new resistance
$
R^{\prime}=\rho \frac{l^{\prime}}{A^{\prime}}=\rho \frac{(l / 4)}{4 A}=\frac{1}{4 \times 4}\left(\rho \frac{l}{A}\right)=\frac{R}{16}\left(\because R=\rho \frac{l}{A}\right)
$
Thus, the new resistance is $\frac{1}{16}$ of the original resistance.

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Explore more

More "[2 Mark Questions]" from PART - 3 CH - 11 Electricity→PART - 3 CH - 11 Electricity — all question types→Science STD 10 question papers→Gujarat Board STD 10 question papers→Gujarat Board question paper generator→

Similar questions

Blue crystals of copper sulphate on heating in a dry test tube become colourless. Why?

Why is sodium kept immersed in kerosene oil?

How is equal genetic contribution of male and female parents ensured in the progeny?

Write the balanced chemical equation of reaction of sodium carbonate and sodium hydrogencarbonate with dilute hydrochloric acid.

How do desert plants differ from other plants grown in normal habitat on the basis of reduction of CO₂?

Explain in brief : Biomagnification

How does binary fission differ from multiple fission?

We wish to obtain an eree. image of an object, using a concave mirror of focal length 15 cm. What should be the range of distance of the object from the mirror? What is the nature of the image? Is the image larger or smaller than the object? Draw ray diagram to show the image a formation in this case.

Metallic oxides of zinc, magnesium and copper were heated with the following metals :

Metal	Zinc	Magnesium	Copper
Zinc oxide
Magnesium oxide
Copper oxide

In which cases will you find displacement reactions taking place?

Why are molecular movements needed for life?