Question

A 60 W bulb is connected to 120 V source. Find the resistance of the bulb.​

Answer 1

Given :-

Power of the bulb = 60 W

Voltage of the bulb = 120 V

To Find :-

The resistance of the bulb.​

Analysis :-

Here we are given with the power and voltage of the bulb.

In order to find the resistance, substitute the given values in the question using the formula of power is equal to voltage square divided by resistance of the bulb.

Solution :-

We know that,

• p = Power
• v = Voltage
• r = Resistance

Using the formula,

$\underline{\boxed{\sf Power=\dfrac{Voltage^2}{Resistance} }}$

Given that,

Voltage (v) = 120 V

Power (p) = 60 W

Substituting their values,

⇒ p = v²/r

⇒ 60 = 120²/r

⇒ r = 120²/60

⇒ r = 14400/60

⇒ r = 1440/6

⇒ r = 240 Ω

Therefore, the resistance of the bulb is 240 Ω.

Answer 2

Answer:

240 Ω

Explanation:

Given that:-

power of the bulb :-60 W

Voltage of the bulb = 120 V

To find:-

The resistance of the bulb

Solution:-

We now that ,

• P = Power
• V = Voltage
• R = Resistance

Using the formula of :-

$power = \frac{voltage ^{2} }{resistance}$

Given that :-

Voltage (V) = 120 V

Power (P) = 60 W

Substituting the Values :-

$p = \frac{ {v}^{2} }{r}$

$= > 60 = \frac{ {120}^{2} }{60}$

$r = \frac{14400}{60}$

$r = \frac{1400}{6}$

=> r = 240 Ω

Therefore the resistance of the bulb is = 240 Ω