Question

An electric heater works at $ 230\,V $ produces $ 1000 $ J energy in one second.
(A) What is the power of the lamp?
(B) Calculate the resistance of the heating coil used in it.
(C) Calculate the heat generated by it when it works for $ 5 $ minute.

Answer 1

Hint: The conversion of electrical energy to heat energy is known as electric heating. Space heating, cooking, water heating, and industrial activities are all common uses. An electric heater is a device that transforms a current of electricity into heat.Every electric heater's heating element is an electrical resistor that works on the concept of Joule heating, which states that an electric current travelling through a resistor converts electrical energy into heat energy. Most modern electric heating systems use nichrome wire as the active element; the heating element on the right is nichrome wire supported by ceramic insulators.
 $ P = \dfrac{H}{t} $
 $ R = \dfrac{{{V^2}}}{P} $
 $ H = Pt $
Where,
 $ P = $ Power, $ R = $ Resistance, $ V = $ Voltage, $ t = $ Time, $ H = $ Heat.

Complete answer:
 $ H{\text{ }} = {\text{ }}{I^2}Rt $ is the heating effect caused by an electric current, $ I $ , flowing through a resistance conductor, $ R $ , for a specified duration, $ t $ . The Joule's equation of electrical heating is the name given to this equation.
 $ H{\text{ }} = {\text{ }}{I^2}Rt $
We can write:
 $ H = Pt $
 $ P = \dfrac{H}{t} $
Given:
Heat $ = 1000\,J $
(a)
So as we know power is given by:
 $ P = \dfrac{{1000}}{1} = 1000\,watt $
(b)
The resistance of the heating coil is :
 $ R = \dfrac{{{V^2}}}{P} $
Given:
 $ V = 230\,V $
 $ R = \dfrac{{{{230}^2}}}{{1000}} = 52.9\Omega $
(c)
Heat generated:
Heat $ H = Pt $ $ = 1000 \times 5 \times 60 = 300000J $ .

Note:
Electrical energy is turned into heat energy when a current travels across a resistor. The rate at which heat is dissipated is referred to as power, denoted by the letter P and measured in Watts (W). Any two of the quantities used in Ohm's law calculations can be utilised to calculate the amount of power dissipated.