EASY

12th CBSE

IMPORTANT

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The following table gives the length of three copper wires, their diameters, and the applied potential difference across their ends. Arrange the wires in increasing order according to the following:

Wire No. Length Diameter Potential difference

$1$ $l$ $3 d$ $V$

$2$ $2 l$ $d$ $V$

$3$ $3 l$ $2 d$ $2 V$

The current density within them.

Important Questions on Current Electricity

EASY

12th CBSE

IMPORTANT

New Simplified Physics (Vol 1) For Class 12>Chapter 3 - Current Electricity>SHORT ANSWER CONCEPTUAL PROBLEMS>Q 17

Two metallic wires,

P_{1}

and

P_{2}

of the same material and same length but different cross-sectional areas,

A_{1}

and

A_{2}

are joined together and connected to a source of emf. Find the ratio of the drift velocities of free electrons in the two wires when they are connected in series.

EASY

12th CBSE

IMPORTANT

New Simplified Physics (Vol 1) For Class 12>Chapter 3 - Current Electricity>SHORT ANSWER CONCEPTUAL PROBLEMS>Q 17

Two metallic wires,

P_{1}

and

P_{2}

of the same material and same length but different cross-sectional areas,

A_{1}

and

A_{2}

are joined together and connected to a source of emf. Find the ratio of the drift velocities of free electrons in the two wires when they are connected in parallel.

EASY

12th CBSE

IMPORTANT

New Simplified Physics (Vol 1) For Class 12>Chapter 3 - Current Electricity>SHORT ANSWER CONCEPTUAL PROBLEMS>Q 18

Three materials

A

B

and

C

have electrical conductivities

σ

2 σ

and

2 σ

respectively. Their number densities of free electrons are

n

2 n

and

n

respectively. For which material, is the average collision time of free electrons maximum?

EASY

12th CBSE

IMPORTANT

New Simplified Physics (Vol 1) For Class 12>Chapter 3 - Current Electricity>SHORT ANSWER CONCEPTUAL PROBLEMS>Q 19

A battery of emf

ε

and internal resistance

r

sends currents

I_{1}

and

I_{2}

, when connected to external resistances

R_{1}

and

R_{2}

respectively. Find the emf and the internal resistance of the battery.

EASY

12th CBSE

IMPORTANT

New Simplified Physics (Vol 1) For Class 12>Chapter 3 - Current Electricity>SHORT ANSWER CONCEPTUAL PROBLEMS>Q 20

Two identical storage batteries, each having emf e and internal resistance $r$ , are connected, as shown in Fig. Determine the potential difference set up between the points $A$ and $B$ .

Question Image

EASY

12th CBSE

IMPORTANT

New Simplified Physics (Vol 1) For Class 12>Chapter 3 - Current Electricity>SHORT ANSWER CONCEPTUAL PROBLEMS>Q 21

A battery of emf e and internal resistance

r

is connected to a variable external resistance

R

. Find the value of

R

for which current in the circuit is maximum.

EASY

12th CBSE

IMPORTANT

New Simplified Physics (Vol 1) For Class 12>Chapter 3 - Current Electricity>SHORT ANSWER CONCEPTUAL PROBLEMS>Q 21

A battery of emf e and internal resistance

r

is connected to a variable external resistance

R

. Find the value of

R

for which terminal p.d. across the battery is maximum. Also, find the maximum value of current in case (i) and maximum terminal p.d. in case (ii).

EASY

12th CBSE

IMPORTANT

New Simplified Physics (Vol 1) For Class 12>Chapter 3 - Current Electricity>SHORT ANSWER CONCEPTUAL PROBLEMS>Q 22

Under what conditions will the strength of current in a wire be the same for connections in series and in parallel of identical cells?

Wire No.	Length	Diameter	Potential difference
$1$	$l$	$3 d$	$V$
$2$	$2 l$	$d$	$V$
$3$	$3 l$	$2 d$	$2 V$

Important Questions on Current Electricity

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