Physics, asked by bhavan3, 1 month ago

two electric bulb of 40 w and 60 w connected to 120v line the ratio of there resistance wil be​

Answers

Answered by sachingavakari
1

1:12 is your right answer to your question

Answered by rishikeshm1912
0

Given:

Power of 1st electric bulb = 40W

Power of 2nd electric bulb = 60W

Potential across them = 120V

To find:

Ratio of resistances of two bulbs.

Solution:

Formula of power dissipated is-

P = \frac{V^2}{R}= I^2R = VI

here, P = power dissipated

        V = potential across the resistance

          I = current flowing across the resistance

In this question, to calculate resistance we will use the below formula,

P = \frac{V^2}{R}

therefore, R = \frac{V^2}{P}

Resistance of first electric bulb will be -

   R_1 = \frac{V^2}{P_1}

here, P₁ = 40W

         V = 120V

R_1 = \frac{(120)^2}{40}

R₁ = 360Ω

and, Resistance of second electric bulb is-

   R_2 = \frac{V^2}{P_2}

   R_2 = \frac{(120)^2}{60}

   R₂ = 240 Ω

Therefore, ratio of first resistance to the second resistance will be,

\frac{R_1}{R_2} = \frac{360}{240}

\frac{R_1}{R_2} = \frac{3}{2}

So, the ratio of resistance having power dissipated value 40W to the resistance having power dissipated value 60W is 3:2.

           

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