A Carnot engine whose sink is at $300 \,K$ has an efficiency of $50 \%$. By how much should the temperature of source be increased so as the efficiency becomes $70 \%$ is ............ $K$
Medium
Download our app for free and get startedPlay store
(d)

Temperature of sink; $T_2=300 K$

Original efficiency; $\eta=50 \%=0.5$

Let initial temperature $: \rightarrow T_1$

we know; $\eta=1-\frac{T_2}{T_1}$

Substituting the values we get:

$0.5=1-\frac{300}{T_1}$

$\Rightarrow T_1=600\,K$

Now; new efficiency; $\eta^{\prime}=70 \%=.7$

New initial temperature $=T_1^{\prime}$

$\Rightarrow 0.7=1-\frac{T_2}{\left(T_1\right)^{\prime}}$

$\Rightarrow 0.7=1-\frac{300}{\left(T_1\right)^{\prime}}$

$\Rightarrow\left(T_1\right)^{\prime}=1000\,K$

$\therefore$ Increase in source temperature is:

$\Delta T =(1000-600)\,K$

$\Rightarrow \Delta T =400\,K$

So the temperature of the source should be increased by $400\,K$.

art

Download our app
and get started for free

Experience the future of education. Simply download our apps or reach out to us for more information. Let's shape the future of learning together!No signup needed.*

Similar Questions

  • 1
    A cyclic process $ABCD$ is shown in the figure $P-V$ diagram. Which of the following curves represent the same process
    View Solution
  • 2
    $Assertion :$ When a glass of hot milk is placed in a room and allowed to cool, its entropy decreases.
    $Reason :$ Allowing hot object to cool does not violate the second law of thermodynamics.
    View Solution
  • 3
    Two cylinders contain same amount of ideal monatomic gas. Same amount of heat is given to two cylinders. If temperature rise in cylinder $A$ is $T_0$ then temperature rise in cylinder $B$ will be .........
    View Solution
  • 4
    A thermodynamic system is taken through the cycle $ABCD$ as shown in figure. Heat rejected by the gas during the cycle is 
    View Solution
  • 5
    For an adiabatic expansion of an ideal gas, the fractional change in its pressure is equal to (where $\gamma$ is the ratio of specific heats):
    View Solution
  • 6
    The efficiency of a Carnot engine operating with reservoir temperature of $100\,^{\circ} C$ and $-23\,^{\circ} C$ will be
    View Solution
  • 7
    Answer the following by appropriately matching the lists based on the information given in the paragraph.

    In a thermodynamics process on an ideal monatomic gas, the infinitesimal heat absorbed by the gas is given by $T \Delta X$, where $T$ is temperature of the system and $\Delta X$ is the infinitesimal change in a thermodynamic quantity $X$ of the system. For a mole of monatomic ideal gas

    $X=\frac{3}{2} R \ln \left(\frac{T}{T_A}\right)+R \ln \left(\frac{V}{V_A}\right)$. Here, $R$ is gas constant, $V$ is volume of gas, $T_A$ and $V_A$ are constants.

    The $List-I$ below gives some quantities involved in a process and $List-II$ gives some possible values of these quantities.

    List-$I$ List-$II$
    $(I)$ Work done by the system in process $1 \rightarrow 2 \rightarrow 3$ $(P)$ $\frac{1}{3} R T_0 \ln 2$
    $(II)$ Change in internal energy in process $1 \rightarrow 2 \rightarrow 3$ $(Q)$ $\frac{1}{3} RT _0$
    $(III)$ Heat absorbed by the system in process $1 \rightarrow 2 \rightarrow 3$ $(R)$ $R T _0$
    $(IV)$ Heat absorbed by the system in process $1 \rightarrow 2$ $(S)$ $\frac{4}{3} RT _0$
      $(T)$ $\frac{1}{3} RT _0(3+\ln 2)$
      $(U)$ $\frac{5}{6} RT _0$

    If the process carried out on one mole of monatomic ideal gas is as shown in figure in the PV-diagram with $P _0 V _0=\frac{1}{3} RT _0$, the correct match is,

    $(1)$$I \rightarrow Q, II \rightarrow R , III \rightarrow P , IV \rightarrow U$

    $(2)$ $I \rightarrow S , II \rightarrow R , III \rightarrow Q , IV \rightarrow T$

    $(3)$ $I \rightarrow Q , II \rightarrow R , III \rightarrow S , IV \rightarrow U$

    $(4)$ $I \rightarrow Q , II \rightarrow S , III \rightarrow R , IV \rightarrow U$

    ($2$) If the process on one mole of monatomic ideal gas is an shown is as shown in the $TV$-diagram with $P _0 V _0=\frac{1}{3} RT _0$, the correct match is

    $(1)$ $I \rightarrow S, II \rightarrow T, III \rightarrow Q , IV \rightarrow U$

    $(2)$ $I \rightarrow P , II \rightarrow R, III \rightarrow T , IV \rightarrow S$

    $(3)$ $I \rightarrow P, II \rightarrow, III \rightarrow Q, IV \rightarrow T$

    $(4)$ $I \rightarrow P, II \rightarrow R, III \rightarrow T, IV \rightarrow P$

    Give the answer or quetion $(1)$ and $(2)$

    View Solution
  • 8
    Select the correct statement for work, heat and change in internal energy.
    View Solution
  • 9
    One mole of an ideal gas expands at a constant temperature of $300 \,K$ from an initial volume of $10\, litres$ to a final volume of $20\, litres$. The work done in expanding the gas is ...... $J.$ $(R = 8.31 J/mole-K)$
    View Solution
  • 10
    Out of the following which quantity does not depend on path
    View Solution