Question

when two bulbs of power 60w and 40w are connected in series then the power of their combination will be​

Answer 1

answer : 24W

explanation : when two bulbs of power 60w and 40w are connected in series , then we have to find power of their combination.

we know, power,$P=\frac{V^2}{R}$

where V denoted voltage across the circuit and R denotes resistance of bulb.

so, resistance of first bulb , $R_1=\frac{V^2}{P_1}$

= V²/60 .....(1)

Similarly, resistance of 2nd bulb, $R_2=\frac{V^2}{P_2}$

= V²/40 ........(2)

now , if $R_1$ and $R_2$ are joined in series then,

equivalent resistance, $R_{eq}=R_1+R_2$

or, $\frac{V^2}{P_{eq}}=\frac{V^2}{60}+\frac{V^2}{40}$

or, $\frac{1}{P_{eq}}=\frac{1}{60}+\frac{1}{40}$

hence, $P_{eq}=\frac{60\times40}{60+40}=24W$

hence, power of their combination is 24W.

[note : you can just use formula, $\frac{1}{P_{eq}}=\frac{1}{P_1}+\frac{1}{P_2}$ ]

Answer 2

When two bulbs of power 60 watt and 40 watt are connected in series then the resulting power their combination will be​ 24 watt.

Answer: 24 watt

Explanation:

The two bulbs such that the power rating of the bulbs are 60 watt and 40 watt respectively and the two bulbs are connected in series.  

If V is the voltage across the resistance and R is the value of resistance then the power is given as

$P = 60, P = 40$

Power,  $P = \frac{(V^2)}{R}$

On interchanging we get R equal to $R=\frac{(V^2)}{P} .... (1)$

From the above given equation (1) we have the value of two resistances as

Resistance of 1st bulb $R_1 =\frac{V^2}{P_1} ..... (2)$

Similarly, Resistance of 2nd bulb $R_2 = \frac{V^2}{P_2} ..... (3)$

By substituting, the power value of 60 watt and 40 watt in the equation (2) and (3)

We get $R_1=\frac{V^2}{60}$ and $R_2=\frac{V^2}{40}$

So now equivalent resistance $R_eq=R_1+R_2$

$R_eq=\frac{V^2}{60}+\frac{V^2}{40}$

Hence, $P_eq=\frac{1}{60}+\frac{1}{40}$

⇒ $P_eq=\frac{40\times60}{60+40}$

There, Power combination is 24 watt.

To Know more:

Two bulbs of power 60W and 40W are connected in series, then what is the power of combination?

https://brainly.in/question/8270258