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## Class 10 Physics (India)

### Course: Class 10 Physics (India)>Unit 3

Lesson 7: Electric power and heating effect of current

# Heating effect of current

We will explore what causes things to heat up when electricity runs through them. We will also learn how to calculate the amount of heat produced per second due to electricity. Created by Mahesh Shenoy.

## Want to join the conversation?

• onwards, how is the amount of energy being lost equal to the heat dissipated? Isn't energy also used for useful things and not just wasted as heat? • There's no other thing for that resistor to do. The potential energy lost has to be dissipated as heat, as it can't pile up there. In the case of incandescent bulbs, the filament turns so hot that some energy turns into light. Other than that, there's no other energy conversion, or so I think.

Hope that helps. :)
I find definition of current but did not the same for ELECTRICITY?
It looks these two are used interchangeably in lecture • Well here we learnt that electricity can be directly converted to heat and Faraday discovered magnetic to electricity as electromagnetic induction we all know. So from these two can't we mean something like directly from heat to electricity instead of going through long chain of heat - mechanical - magnetic - electrical losing most of energy and this won't happen this huge if gone direct if we succeed to do so?

Thanks
Deep
(1 vote) Can't we use the heat dissipated by converting/transferring it back to electrical energy?
(1 vote) • is heat also equal to Voltage x Net charge (Q)?
(1 vote) • The relationship between heat (Q), voltage (V), and net charge (Q) is not expressed simply as
Q=V⋅Q. The correct relationship between electrical energy, voltage, and charge is given by the equation:

Q=V⋅C

Here,
Q is the electric charge in coulombs,
V is the voltage in volts, and
C is the capacitance of the system in farads.

The relationship between heat and electrical energy involves additional factors, particularly in the context of thermodynamics. In a resistive electrical element, where current flows and voltage is applied, the heat generated (Q) can be calculated using Joule's law:

Q=I⋅V⋅t

Where:
Q is the heat generated,
I is the current flowing through the resistor,
V is the voltage across the resistor, and
t is the time for which the current flows.

So, while there is a relationship between electrical energy and heat, it involves the current, voltage, and time, rather than a direct multiplication of voltage and charge.
(1 vote)
• Why does the wire of the heater not glow while the heating element does?
(1 vote) • " the light that we get is because of the heat that is generated due to electricity" How? I knew that the lamp produce light and heat

@ did Joule discover this formula experimentally before ohm's law?
(1 vote) • there are two electric bulbs, 1 marked 60w, 220v and 2 marked 100w; 220v. which one of them has higher resistance?
(1 vote) • Hey there,
You can solve this mathematically as answered by @Pruthvi Sriram,
I'll just add to the answer by providing a sol. which is more generalized and quicker,(using the formula for finding power)
P=VI
Here V is constant(220V)
I=V/P (ohm's law)
P= (V^2)/R
(so far the same as @Prithvi Sriram mentioned, but here's the shortcut)
if v is constant v^2 will also be constant
P is inversely proportional to R
if P increases, R decreases
that is why the 2nd bulb offers more resistance
remember---only if V is constant

BONUS
if I is constant (then, v has to change as the resistors offer different resistance)
P will be directly proportional to I,
(P=VI)
then the device with the lowest power will have the highest resistance
(1 vote)
• is r directly or indirectly proportional to heat
(1 vote) • How is the energy released from the bulb taken as heat? Some of the energy is converted to light, right?
(1 vote) 