Tag: joule's law of heating

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Questions Related to joule's law of heating

Multiple choice physics effects of electric current joule's law of heating thermal effect of electric current heating effect of electric current

A/c to Joules's law, if the potential difference across a conductor having a material of specific resistance (P) remains constant, then the heat produced in the conductor is directly proportional to

  1. $\displaystyle P$

  2. $\displaystyle { P }^{ 2 }$

  3. $\displaystyle \frac { 1 }{ \sqrt { P } } $

  4. $\displaystyle \frac { 1 }{ P } $
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Let the specific resistance of the material be  $P$.

$\therefore$  Resistance of the conductor        $R = \dfrac{P L}{A}$
According to Joule's heating effect,  heat produced     $H = \dfrac{V^2t}{R}$

$\therefore$   $H = \dfrac{V^2 t}{PL/A}  = \dfrac{V^2A t}{L}\dfrac{1}{P}$              $\implies H\propto \dfrac{1}{P}$

Multiple choice physics effects of electric current joule's law of heating thermal effect of electric current heating effect of electric current

Joule's heating effect is

  1. Reversible

  2. Irreversible

  3. Both

  4. None
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Joule heating effect is irreversible that means if the direction of current in a resistor is reversed, the cooling of resistor does not occur whereas heating of the resistor takes place.

Heat produced via Joule's heating effect    $H = i^2Rt$ 

Multiple choice physics effects of electric current joule's law of heating thermal effect of electric current heating effect of electric current

J (Joule's mechanical equivalent of heat) is equal to

  1. 2400J

  2. $\displaystyle 4.18J{ cal }^{ -1 }$

  3. $\displaystyle 2.2J{ cal }^{ -1 }$

  4. 1000J
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
According to Joule's law, mechanical equivalent of heat    $J = \dfrac{W}{Q}$
Mathematically    $J = 4.18$  $Jcal^{-1}$ if work done and heat produced is measured in joules and calories respectively.
Multiple choice physics effects of electric current joule's law of heating thermal effect of electric current heating effect of electric current

From below which one is the equation for Joule's law of heating effect of electricity?

  1. $H=I^2Rt$

  2. $H=IR^2t$

  3. $H=IRt^2$

  4. $H=\dfrac{It^2}{R}$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

According to Joule's law of heating,  heat produced in a resistor     $H = I^2Rt$

where $I$ and $t$ are the current flowing through the resistor and time of current flowing respectively.

Multiple choice physics effects of electric current joule's law of heating thermal effect of electric current heating effect of electric current

 When electric current is passed through conductor i.e. generates heat due to resistance it offers to current flow. What this phenomena known as :

  1. Burning effect of electricity

  2. Potential Effect of electricity

  3. Heating effect of electricity

  4. Floating effect of electricity
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The phenomenon of generating heat due to the resistance of the conductor when a current passes through it is known as heating effect of electricity.

Heat produced     $H = I^2Rt$

Multiple choice physics effects of electric current joule's law of heating thermal effect of electric current heating effect of electric current

Which of the following terms does not represent electrical power in a circuit?

  1. $I^2R$

  2. $IR^2$

  3. $VI$

  4. $V^2/R$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

$P=VI\quad .............(i)$

Hence, option (c) represents power.
$V=IR\quad .............(ii)$

From (i) and (ii),
$P=I^2R$
$P=V^2/R$
Hence, option (a) and (d )represents power too.
Option (b) does not represent power.

Multiple choice physics effects of electric current joule's law of heating thermal effect of electric current heating effect of electric current

A $1000\Omega$ electric iron is connected to $200v$, $50Hz$ ac source. Calculate average power delivered to iron, peak power and energy spent in one minute?

  1. $400W,\ 800W,\ 12\times 10^{5}\ J$

  2. $400W,\ 900W,\ 1.2\times 10^{5}\ J$

  3. $500W,\ 800W,\ 6\times 10^{5}\ J$

  4. $400W,\ 900W,\ 60\times 10^{5}\ J$
Reveal answer Fill a bubble to check yourself
A Correct answer