Question

36. We have two wires A and B of same mass and same material. The diameter of the wire Ais
half of that B. If the resistance of wire Ais 24 ohm then the resistance of wire B will be
a) 12 ohm b ) 3.0 ohm C) 1.5 ohm

Answer 1

Answer:

(C) 1.5 Ohm

Explanation:

Hope this helped you!!

Answer 2

Answer:

$\LARGE{ \underline{ \bf{Required \: answer:}}}$

$\large{ \boxed{ \boxed{ \rm{1.5 \: ohm}}}}$

Explanation:

We have,

Resistance of 1 m wire = 3 Ω

Now, we know that resistance is directly proportional to length and is given by R = Resistivity × Length / Cross-sectional Area. Resistivity and Cross sectional area will remain same, then Resistance will vary with length.

Then,

Resistance of 1.5 m wire = 3 × 1.5 Ω = 4.5 Ω

So, we have three lengths of resistors with resistance 4.5 Ω. They are connected in parallel. Then equivalent resistance:

$\rm{ \dfrac{1}{R_eq.} = \dfrac{1}{R_1} + \dfrac{1}{R_2} + \dfrac{1}{R_3}}$

We have, R1 = R2 = R3. Hence Req. = R/3

$\rm{R_eq. = \dfrac{4.5}{3} } = 1.5 ohm$

And we are done! :D