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

Which of the following statement is correct?

  1. seebeck effect is irreversible.

  2. Thomson effect is localised at the junction.

  3. Joule heating effect is indeoendent of the direction of flow of current in a conductor.

  4. Thomson effect is similer in origin to pelteir effect. They both are due to non-uniform distribution of electrons in a metal.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Joule heating (also referred to as resistive or ohmic heating) describes the process where the energy of an electric current is converted into heat as it flows through a resistance.

In particular, when the electric current flows through a solid or liquid with finite conductivity, electric energy is converted to heat through resistive losses in the material. The heat is generated on the microscale when the conduction electrons transfer energy to the conductor's atoms by way of collisions. It does not depend upon the direction of flow of current, but its amount.

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

An electric iron draws a current of 15 A from a 220 V supply, What is the cost of using iron for 30 min everyday for 15 days if the cost of unit (1 unit =1 kWhr) is 2 rupees ? 

  1. Rs 49.5

  2. Rs 60

  3. Rs 40

  4. Rs 10
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

As we know that power(P)=v$\times$I
so P=15$\times$220=3300 watt
cost per unit=2 rupees 
therefore,$\dfrac {3300\times2\times15\times30}{60\times1000}$=49.5 rupees.

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

What is the Joule's law ?

  1. $H=VRt$

  2. $H=I^2R^2t$

  3. $H=I^2Rt$

  4. $H=\dfrac{V^2}{R}t$
Reveal answer Fill a bubble to check yourself
C,D Correct answer
Explanation

Joules law can be stated as the quantity of heat generated (H) in a conductor of Resistance (R), when a current (I) flows through it for a time (t) is directly proportional to the square of the current, the resistance of the conductor, and the time for which the current flows.
So, $H=I^2Rt$
Now, for a conductor following Ohm's Law, $V=IR$, or, $I=\dfrac{V}{R}$
Therefore, $H=\dfrac{V^2}{R^2} \times R \times t=\dfrac{V^2}{R}t$

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

The power dissipated as heat in a conductor of resistance $R$ due to current $I$ through it is called ________.

  1. Joule's loss

  2. $I^2R$ loss

  3. Either $(1)$ or $(2)$

  4. Neither $(1)$ nor $(2)$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The loss in power in electric circuit due to heat produced in conductors due to their resistance is called $Joule's \hspace{2mm} heat$.


Heat loss is given by $I^2R$.

Answer-(C)

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

Laws of heating are given by

  1. Joule

  2. Ohm

  3. Maxwell

  4. Faraday
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Laws of heating are given by Joule 

Joule's Heating Effect:- When an electric current is passed through the conductor, it becomes hot and its temperature starts rising. This is known as the heating effect of current or Joule's heating effect.

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

A given quantity of water boils in an electric kettle in $12 min$. The length of the heating element in the kettle is $\iota $. If the same quantity of water is to boil in $10 min$ on the same mains the length of an identical heating element is _______.

  1. $\iota $

  2. $\displaystyle \frac {\iota }{2}$

  3. $\displaystyle \frac {3\iota }{4}$

  4. $\displaystyle \frac {5\iota }{6}$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Amount of heat required to boil a given quantity of water in a constant

$\displaystyle P=\frac {W}{t}$ or $W = H = P \times t = \displaystyle \frac {V^2}{R} \times t = \displaystyle \frac {V^2t _1}{R _1} = \displaystyle \frac {V^2t _2}{R _2}$

$\displaystyle \Rightarrow \frac {t _2}{t _1} = \frac {R _2}{R _1} = \frac {l _2}{l _1}$

or $\displaystyle \frac {10}{12} = \frac {l _2}{l _1} \Rightarrow l _2 = \frac {10}{12} \times l _1$

$\displaystyle l _2 = \frac {5}{6}l$

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

For a constant power source across a resistor, heat generated in a resistor:

  1. increases with increase in resistance

  2. increases with increase in applied potential

  3. increases with decrease in resistance

  4. is constant
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Heat generated across the resistor is given by

$Q=I^2Rt = VIt$
Since, power supplied is constant,
$VI = \text{constant}$
$\implies Q = constant$ 

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

How much heat, in joules, must be added to 0.250 mol of Ar(g) to raise its temperature from 20.0 to $36.0^\circ C$ of at constant pressure?

  1. $50.0J$

  2. $83.14J$

  3. $18J$

  4. $200J$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

At constant pressure,
$q=nCp  \Delta t$               $C _p =\frac{5R}{2}$
$=(0.25) \left ( \frac{5}{2} \times 8.314  \right ) (16)$
$=83.14 J$

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

The $1847$ Joule's experiment was aimed at.

  1. Determining the mechanical equivalent of heat

  2. Determining the temperature for the maximum density of water

  3. Investigating the heating effect of electric current

  4. Investigating the internal energy of a gas
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

James Prescott Joule performed experiments in the 1840s to demonstrate that heat is a form of energy. His work established the mechanical equivalent of heat, showing that a specific amount of mechanical work could produce a specific amount of heat.