CBSE 11th Standard Physics Subject Thermodynamics HOT Questions 5 Mark Questions With Solution 2021
By QB365 on 29 May, 2021
QB365 Provides the HOT Question Papers for Class 11 Physics, and also provide the detail solution for each and every HOT Questions. HOT Questions will help to get more idea about question pattern in every exams and also will help to get more marks in Exams
QB365 - Question Bank Software
CBSE 11th Standard Physics Subject Thermodynamics HOT Questions 5 Mark Questions With Solution 2021
11th Standard CBSE
-
Reg.No. :
Physics
-
The efficiency of a Carnot engine is 1/2. If the sink temperature is reduced by 100o C, then engine efficiency becomes 2/3. Find
(i) sink temperature
(ii) source temperature
(iii) Explain, why a Carnot engine cannot have 100% efficiency?(a)
*****************************************
CBSE 11th Standard Physics Subject Thermodynamics HOT Questions 5 Mark Questions With Solution 2021 Answer Keys
-
Efficiency , \(\eta =1-\frac { { T }_{ 2 } }{ { T }_{ 1 } } \)
where, T2 = sink temperature
T1 = source temperature.
\(1-\frac { { T }_{ 2 } }{ { T }_{ 1 } } =\frac { 1 }{ 2 } \quad ...(i)\)
\(\\ 1-\left( \frac { { T }_{ 2 }-100 }{ { T }_{ 1 } } \right) =\frac { 2 }{ 3 } \ ...(ii)\)
From Eq. (i), \(\frac { { T }_{ 2 } }{ { T }_{ 1 } } =\frac { 1 }{ 2 } \) and Eq. (ii)
\(\frac { { T }_{ 2 }-100 }{ { T }_{ 1 } } =\frac { 1 }{ 3 } \)
On dividing, we get
\(\frac { { T }_{ 2 } }{ { T }_{ 2 }-100 } =\frac { 3 }{ 2 } \Rightarrow { T }_{ 2 }=300K\)
(ii) Substituting in Eq.(i) T1 = 600K
(iii) As efficiency, \({ \eta }_{ 2 }\Rightarrow 1-\frac { { T }_{ 2 } }{ { T }_{ 1 } } \)
It equals to 1 only when \(\frac { { T }_{ 2 } }{ { T }_{ 1 } } =0\quad or\quad { T }_{ 2 }=0K\)
But absolute zero is not possible.
