MCQ
A Carnot engine with sink's temperature at $17\,^oC$ has $50\%$ efficiency. By how much should its source temperature be changed to increases its efficiency to $60\%$ ?...... $K$
- A$225$
- B$128$
- C$580$
- ✓$145$
✓
Answer
Correct option: D.
$145$
d
$\eta=1-\frac{\mathrm{T}_{2}}{\mathrm{T}_{1}}$
$\eta=1-\frac{\mathrm{T}_{2}}{\mathrm{T}_{1}}$
$\Rightarrow \frac{50}{100}=1-\frac{290}{\mathrm{T}_{1}} \Rightarrow \mathrm{T}_{1}=580 \mathrm{K}$
$\Rightarrow \frac{60}{100}=1-\frac{290}{\mathrm{T}_{1}^{\prime}} \Rightarrow \mathrm{T}_{1}^{\prime}=725 \mathrm{K}$
$\Rightarrow \Delta \mathrm{T}=\mathrm{T}_{1}^{\prime}-\mathrm{T}_{1}=145 \mathrm{K}$
Need a full question paper?
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
Explore more
Similar questions
A rod $C D$ of thermal resistance $10.0\; {KW}^{-1}$ is joined at the middle of an identical rod ${AB}$ as shown in figure, The end $A, B$ and $D$ are maintained at $200^{\circ} {C}, 100^{\circ} {C}$ and $125^{\circ} {C}$ respectively. The heat current in ${CD}$ is ${P}$ watt. The value of ${P}$ is ... .
→A steel wire of lm long and $1\,m{m^2}$ cross section area is hang from rigid end. When weight of $1\,kg$ is hung from it then change in length will be given ..... $mm$ $(Y = 2 \times {10^{11}}N/{m^2})$
→Which of the following are true?
- A polar satellite goes around the earth’s pole in northsouth direction.
- A geostationary satellite goes around the earth in eastwest direction.
- A geostationary satellite goes around the earth in westeast direction.
- A polar satellite goes around the earth in eastwest direction.
The same retarding force is applied to stop a train. The train stops after $80\, m$. If the speed is doubled, then the stopping distance will be
→If $\overrightarrow A \times \overrightarrow B = \overrightarrow C + \overrightarrow D,$ then select the correct alternative-
→A body is moving with velocity $30\; m/s$ towards east. After $10$ seconds its velocity becomes $40\; m/s$ towards north. The average acceleration of the body is ...... $m/s^2$
→$7$ mole of certain monoatomic ideal gas undergoes a temperature increase of $40 K$ at constant pressure. The increase in the internal energy of the gas in this process is$....J$ (Given $R =8.3 JK ^{-1} mol ^{-1}$ )
→It is estimated that per minute each $cm^2$ of earth receives about $2\ cal (1\ cal = 4.18\ J)$ of heat energy from the sun. This is called Solar constant. In $SI$ units the value is
→When a box is in stationary position with respect to train moving with no acceleration, then relative motion is opposed by ______ Which provides the same velocity to the box as that of the train, keeping it stationary relative to the train.
The displacement of a particle is proportional to the cube of time elapsed. How does the acceleration of the particle depends on time obtained