Question

✍️Hola mates ✍️


An electric bulb is rated 220V and 100W. When it is operated on 110V , the power consumed will be

a. 100 W
b. 75 W
c. 50 W
d. 25 W​

Answer 1

Power = 25 W

Explanation:

Given:

• Power of bulb is 100 W.
• Potential difference is 220V.
• Potential difference is 110V.

To Find:

• After operating bulb on 110V power consumed will be ?

Formula to be used:

• P = V²/R

Solution: Here in the first case we have

• P = 100W
• V = 220V

Lets find R by substituting the values in the formula

$\implies{\rm }$ P = V²/R

$\implies{\rm }$ 100 = 220²/R

$\implies{\rm }$ 100R = 48400

$\implies{\rm }$ R = 48400/100

$\implies{\rm }$ R = 484 ohms

Now as given in second case

• P = to be calculated
• V = 110V
• R = 484 ohms (from above)

Put the values on formula

$\implies{\rm }$ P = V²/R

$\implies{\rm }$ P = 110²/484

$\implies{\rm }$ P = 12100/484

$\implies{\rm }$ P = 25 W

Hence the power consumed will be 25 watts.

(Option D is correct)

Answer 2

Answer:

Power = 25 W

Explanation:

Given:

Power of bulb is 100 W.

Potential difference is 220V.

Potential difference is 110V.

To Find:

After operating bulb on 110V power consumed will be ?

Formula to be used:

P = V²/R

Solution: Here in the first case we have

P = 100W

V = 220V

Lets find R by substituting the values in the formula

⟹ P = V²/R

⟹ 100 = 220²/R

⟹ 100R = 48400

⟹ R = 48400/100

⟹ R = 484 ohms

Now as given in second case

P = to be calculated

V = 110V

R = 484 ohms (from above)

Put the values on formula

⟹ P = V²/R

⟹ P = 110²/484

⟹ P = 12100/484

⟹ P = 25 W

Hence the power consumed will be 25 watts.

(Option D is correct)

Explanation:

Hope this answer will help you.✌️