Question

Electricity chapter class X.
Someone please help me.​

Answer 1

$\bold{RESISTANCE}$

Resistance is the obstruction offered in the path of current.

▶When resistors are in parallel total resistance is the sum of reciprocal of all the resistances.

$\boxed{ \dfrac{1}{R_p} = \dfrac{1}{R_1}+\dfrac{1}{R_2}+ n th \: resistors }$

▶When resistors are in series total resistance is the sum of all the resistances.

$\boxed{ R_s = R_1+R_2 + n th \: resistors }$

From given figure we can convey that,

from point C the current gets divided into two parallel parts.

✳In first path three resistors of 3 ohms are in series to each other so, total resistance will be sum of all resistances .

$\mathsf{ R_s = 3 +3+ 3 }$

$\boxed{\mathsf{R_s = 9}}$

✳In second path there is on resistors of 3 ohms

✳For the total resistance we can say total series resistance is parallel to second path resistors So,

$\mathsf{ \dfrac{1}{R_p} = \dfrac{1}{9}+\dfrac{1}{3}}$

$\mathsf{ \dfrac{1}{R_p} = \dfrac{1 + 3}{9}}$

$\mathsf{ \dfrac{1}{R_p} = \dfrac{4}{9}}$

$\mathsf{ R_p = \dfrac{9}{4}}$

$\boxed{\mathsf{Equivalent \: resistance = 2.25 \Omega}}$