Advertisement Remove all ads

An Electric Bulb is Rated 250 W, 230 V. What Information Does this Convey? Calculate the Current Through a 60 W Lamp Rated for 250 V. If the Line Voltage Falls to 200 V, How is the Power - Physics

An electric bulb is rated 250 W, 230 V. What information does this convey? Calculate the current through a 60 W lamp rated for 250 V. If the line voltage falls to 200 V, how is the power consumed by the bulb affected?
Advertisement Remove all ads


'An electric bulb is rated 250 W-230V'; means that if the bulb is lighted on a 230V supply it consumes 25 ow electrical power or 25 OJ of electrical energy converts into heat and light in 1 second.

The safe Ii m it of current through the bulb is:

I = `"P"/"V" = 250/230` = 1.1 A

Current through a 60W lamp rated for 250V is:

I = `"P"/"V" = 60/250` = 0.24 A

We know that resistance of an appliance remains constant.
Resistance of the 1 amp =

R = `"P"/"I"^2 = 60/(0.24)^2 Omega`

If the line voltage falls to 200 V, power =

P = `"V"^2/"R" = (200 xx 200 xx (0.24)^2)/60` = 38.4 watt

Thus power of the lamp reduces to 38. 4 watt.

Concept: Concept of Current Electricity Numericals
  Is there an error in this question or solution?
Advertisement Remove all ads


Frank ICSE Class 10 Physics Part 2
Chapter 4 Current Electricity
Exercise 4.2 | Q 8 | Page 188
Advertisement Remove all ads
Advertisement Remove all ads

View all notifications

      Forgot password?
View in app×