SATHEE: current-electricity Question 23

Current Electricity

current-electricity Question 23

Question: Q. 14. Two cells of E.M.F. $10 V$ and $2 V$ and internal resistances $10 Ω$ and $5 Ω$ respectively, are connected in parallel as shown. Find the effective voltage across $R$

A [CBSE SQP 2015-2016]

Calculate the current drawn from the battery by the network of resistors shown in the figure.

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Solution:

Ans. The given network has the form given below :

It is a balanced Wheatstone Bridge.

Its equivalent resistance, $R$ is given by

$\begin{aligned} \frac{1}{R} & = \frac{1}{1 + 2} + \frac{1}{2 + 4} & = \frac{1}{2} \end{aligned}$

$R = 2 Ω$

$∴$ Current drawn $= \frac{4 V}{2} = 2 A$

AI Q. 16. Estimate the average drift speed of conduction electrons in a copper wire of cross-sectional area $2.5 \times 10^{- 7} m^{2}$ carrying a current of $1.8 A$ . Assume the density of conduction electrons to be $9 \times 10^{28} m^{- 3}$ .

A [O.D. I, II, III 2014]

$Ans. ∵ \begin{aligned} (1) & I & = n e A v_{d} \Rightarrow v_{d} & = \frac{I}{n e A} v_{d} & = \frac{1.8}{9 \times 10^{28} \times 1.6 \times 10^{- 19} \times 2.5 \times 10^{- 7}} m / s & = 0.05 \times 10^{- 2} m / s \end{aligned}$

[CBSE Marking Scheme 2014]

Current Electricity

current-electricity Question 23

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Current Electricity

current-electricity Question 23

Table of Contents

Engineering Preparation

Medical Preparation

NCERT Books & Solutions

Important Resources

Other Resources

Syllabus

Test Platform

Sample Mock Test

Mentorship

NCERT Exercise Video Solution

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