First slide

Electrical power

Question

You are given several identical resistances each of value R = 10Ω and each capable of carrying maximum current of 1 ampere. It is required to make a suitable combination of these resistances to produce a resistance of 5Ω which can carry a current of 4 amperes. The minimum number of resistances of the type R that will be required for this job

Moderate

A

4
B

10
C

8
D

20

Solution

Suppose n resistors are used for the required job. Suppose equivalent resistance of the combination is R' and according to energy conservation its current rating is $i' .$
Energy consumed by the combination = n x (Energy consumed by each resistance)
$\Rightarrow i'^{2} R^{'} = n \times i^{2} R \Rightarrow n = {(\frac{i^{'}}{i})}^{2} \times (\frac{R^{'}}{R}) = {(\frac{4}{1})}^{2} \times (\frac{5}{10}) = 8$

Get Instant Solutions

When in doubt download our app. Now available Google Play Store- Doubts App

Recieve an sms with download link

Doubts App

OR

SCAN ME

Doubts App

Doubts App