ECAT Physics Online Test With Answers

ECAT Physics Online Test

Sr. # Questions Answers Choice
1 An irreversible heat flow from a hot to cold substances of a system, causes the disorder to decrease remains the same increase any one of them
2 If a system undergoes a natural process it will go in the direction that causes the entropy of the system plus the environment to increase, this is another statement of second law thermodynamics first law of thermodynamics third law of thermodynamics none of them
3 In all natural processes where heat flows from one system to another, there is always a net decrease in entropy increase in entropy decrease or increase in entropy none of them
4 When heat is removed from the system negative positive zero any one of them
5 When heat is added into the system then change in entropy is negative positive zero any one of them
6 Which quantity is important in stating the entropy of the system initial entropy final entropy change in entropy none of them
7 Which of the following is a state variable entropy pressure volume all of them
8 The concept of entropy was introduced into the study of thermodynamics in 1856 1865 1656 1685
9 The efficiency of diesel engine is 25% 25 - 30% 35% 35 - 40%
10 No spark plug is needed in petrol engine diesel engine both of them none of them
11 The efficiency of petrol engine is usually not more than 25% to 30% because of friction heat losses both of them none of them
12 On the exaust stroke, the outlet values opens. The residual gases are expelled and piston moves outwards inwards in either way none of these
13 On the power stroke, a spark fires the mixtures causing a rapid increase in pressure and temperature and the burning mixture expands adiabatically isothermally isochorically isobarically
14 On the compression stroke of the petrol engine, the inlet value is closed and the mixture is compressed adiabatically isothermally isochorcally isobarically
15 A typical four stroke petrol engine undergoes how many successive processes in each cycle one two three four
16 Since the absolute scale is independent of the property of the working substance, hence, can be applied at very high temperature very low temperature any one of them none of them
17 The state in which ice, water and vapour coexists in equilibrium is called zero degree celsius zero degree fahrenheit absolute zero 373 K
18 The unit of thermodynamical scale is centigrade fahrenheit kelvin none of them
19 The absolute temperature of the tripple point of water is 100<span style="color: rgb(84, 84, 84); font-family: arial, sans-serif; font-size: small;">°C</span> 4<span style="color: rgb(84, 84, 84); font-family: arial, sans-serif; font-size: small;">°C</span> 373 K 273.16 K
20 The basis to define a temperature scale that is independent of material properties is provided by carbon cycle nitrogen cycle Carnot cycle irreversible cycle
21 Generally a temperature scale is established by using certain physical properties of a material which varies nonlinearly with temperature linearly with temperature either of them none of them
22 Generally a temperature scale is established by one fixed point two fixed point three fixed point four fixed point
23 The efficiency of carnot engine cannot be 100% or one unless cold reservoir is at 100 K 273 K 0 K -273 K
24 Efficiency of carnot engine is independent of the temperature of sink temperature of source nature of the working substances none of them
25 The highest efficiency of a heat engine whose low temperature is 17°C and the high temperature is 200°C is 70% 100% 35% 38%
26 When the temperature of source and sink of a heat engine become equal entropy change will be Zero Max Min -ve
27
During the whole carnot cycle
 Thermal equilibrium is maintained mechanical equilibrium is maintained both the thermal and mechanical equilibriumis maintained both the thermal and mechanical equilibrium is not maintained
28 Which of the following can become a good temporarily magnet iron steel both of them none of them
29 Which of the following can become a good permanent magnet iron steel both of them none of them
30 In a soft iron, domains are easily oriented along external field and do not return to original random positions easily oriented along external field and readily returns to originally random position do no oriented along external field and also do not returns to originally random position none of them
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