Question

An electric bulb marked 25 W and 100 V is connected across 50 V supply Now its power
(1) 25 W
(2) 12.5 W
(4) 50 W
(3) 6.25 W​

Answer 1

Answer:

The power is 6.25 watt.

Explanation:

Given that,

Power P = 25 w

Voltage V = 100 v

The resistance of the bulb is given by

Using formula of power

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

R

V

2

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

P

V

2

Where, R = resistance

P = power

V = voltage

Put the value into the formula

R=\dfrac{100\times100}{25}R=

25

100×100

R=400\ \OmegaR=400 Ω

Now the power is

Using voltage V = 50 v

Put the value into the formula

P = \dfrac{50\times50}{400}P=

400

50×50

P= 6.25\ wattP=6.25 watt

Hence, The power is 6.25 watt.