A piece of wire of resistance R is cut into five equal parts. These parts are

Sail E0 Webinar

Question

A piece of wire of resistance R is cut into five equal parts. These parts are then connected in parallel. If the equivalent resistance of this combination is $R^{^{'}}$ , then the ratio $\frac{R}{R^{^{'}}}$ is:

Options:

A .

\frac{1}{25}

B .

\frac{1}{5}

C .

5

D .

25

Answer: Option D
:
D

Given the wire is cut into 5 equal parts.
Let the initial resistance of the wire be $R$
where $R = ρ \frac{l}{A} \to R \propto l (l e n g t h o f t h e w i r e)$
then, resistance of each one of the five parts $= (\frac{R}{5})$
Equivalent resistance (R') of resistors connected in parallel is given by $\frac{1}{R^{'}} = \frac{1}{R_{1}} + \frac{1}{R_{2}} . . \frac{1}{R_{n}}$
Equivalent resistance (R') of five parts connected in parallel is given by:
$\frac{1}{R^{'}} = \frac{1}{(\frac{R}{5})} + \frac{1}{(\frac{R}{5})} + \frac{1}{(\frac{R}{5})} + \frac{1}{(\frac{R}{5})} + \frac{1}{(\frac{R}{5})} R^{'} = \frac{R}{25}$
Therefore, $\frac{R}{R^{^{'}}} = 25$

Was this answer helpful ?

Next Question

Submit Solution

More Questions on This Topic :

Question 1. Ohm’s Law gives the relation between potential difference and current i.e, voltage is directly and linearly proportio....and current i.e, voltage is directly and linearly proportional to current.

Question 2. 1 kg piece of copper is drawn into a wire of cross-sectional area 1 mm2, and then the same wire is remoulded agai....of the resistance of the first wire to the second wire.

Question 3. Resistance of alloys decreases with the increase in temperature. ....

Question 4. Which of the following represents electrical power dissipated in an electrical circuit? ....

Question 5. The resistivity of all pure metals increase with the rise in temperature. ....

Question 6. Four wires each of the same length, diameter and material are connected to form a square. If the resistance of each wire....R, then equivalent resistance across the opposite corners is :

Question 7. For a constant resistance, the correct relation between heat produced (H) and electric current (I) flowing is: ....

Question 8. The physical quantity that determines the rate at which energy is delivered by an electric current is ___. ....

Question 9. How much electrical energy flows through a wire in 1 second when the power is 1 kW? ....

Question 10. In a Xerox machine, the black ink's toner particles are negatively charged. They strongly stick to the white A4 s....could the A4 sheet possess for this process to happen?

Chapter 1 - GLOBAL STEEL SCENARIO & INDIAN STEEL INDUSTRY Part 1 : (13-04-2024) INDUSTRY AND COMPANY AWARENESS (ICA)

Direction Sense Test Part 1 Reasoning (Hindi)

Chapter 1 - RMHP / OHP / OB & BP Part 1 : (14-02-2024) GPOE

Cube & Cuboid Part 1 Reasoning (Hindi)

Data Interpretation (DI) Basic Concept Reasoning (Hindi)

Counting Figures Part 1 Counting Of Straight Lines Reasoning (Hindi)

Sail E0 free webinar Webinars

Real Numbers Part 7 Class 10 Maths

Real Numbers Part 1 Class 10 Maths

Polynomials Part 1 Class 10 Maths

GPOE / GPA Combined 1 Free Mock Test SAIL JO E-0 2024

Chapter 3.1 : INTRODUCTION Chapter 3 : Sinter Plant SAIL E0 - GPOE/GPA 2024

Chapter 2.3 : COAL HANDLING PLANT - Set 1 Chapter 2 : Coke Ovens and Coal Chemicals SAIL E0 - GPOE/GPA 2024

Chapter 1.1 : INTRODUCTION Chapter 1 : Raw Material Handling Plant SAIL E0 - GPOE/GPA 2024

DSP Combined 1 Free Revision Test SAIL JO E-0