ECAT Pre General Science Physics Online Test With Answers

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ECAT Pre General Science Physics Online Test

Sr. # Questions Answers Choice
1 A signal appears after amplification, at the output terminal with a phase shift of 180° , if it is applied at inverting input non-inverting input any one of the input terminal none of them
2 OP-AMP has the following input terminals one two three four
3 The amplifier which us used to perform mathematical operations electronically is known as calculator OP-AMP computer any one of them
4 When a transistor is used as a switch the circuit in which the current is to be switched OFF and ON, is connected between the base and emitter collector and emitter base and collector any one of these
5 The emitter-base junction of a transistor is forward-biased and collector-base junction is reverse-biased. If the base current is increased, its I<sub>c</sub>will decrease V<sub>CE</sub>will increase I<sub>C</sub>will increase V<sub>CC</sub>will increase
6 When the emitter-base junction of a transistor is reverse biased, collector current Reverses Increases Decreases Stops
7 The value of current gain of n-p-n transistor is of the order of tens hundreds thousands ten thousands
8 For a n-p-n transistor, the conventional current equation can be written as I<sub>E</sub>+ I<sub>C</sub>= I<sub>B</sub> I<sub>C</sub>- I<sub>B</sub>= I<sub>E</sub> I<sub>C</sub>+ I<sub>B</sub>= I<sub>E</sub> I<sub>B</sub>+ I<sub>E</sub>= I<sub>C</sub>
9 In a normally biased n-p-n transistor, an electron c current IEflows from the emitter into the base collector into the base base into collector none of these
10 In n-p-n transistor, emitter base junction is kept reversed forward biased may be reversed or may be forward biased none of these
11 For normal operation of transistor, the batteries V<sub>CC</sub>is of much lower value than V<sub>BB</sub> V<sub>CC</sub>is of much higher value than V<sub>BB</sub> V<sub>CC is equal to</sub>V<sub>BB</sub> none of these
12 For the normal operation of the transistor, its emitter-base and collector base junctions are forward biased emitter-base junction is reversed biased and collector base junction is forward biased emitter-base junction is forward biased and collector-base junction is reverse biased any one of these
13 Which of the following has a great concentration of impurity base emitter collector none of these
14 In a transistor, the central region is called collector emitter base none of them
15 In a transistor, if the central region is n-type, then this type of transistor is known as n-p-n transistor p-n-p transistor either of these none of these
16 A process is a reversible process, if the entropy of the system increases decreases remains constant none of them
17 The disorder in the system increases due to the removal of heat addition of heat removal or addition of heat none of them
18 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
19 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
20 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
21 When heat is removed from the system negative positive zero any one of them
22 When heat is added into the system then change in entropy is negative positive zero any one of them
23 Which quantity is important in stating the entropy of the system initial entropy final entropy change in entropy none of them
24 Which of the following is a state variable entropy pressure volume all of them
25 The concept of entropy was introduced into the study of thermodynamics in 1856 1865 1656 1685
26 The efficiency of diesel engine is 25% 25 - 30% 35% 35 - 40%
27 No spark plug is needed in petrol engine diesel engine both of them none of them
28 The efficiency of petrol engine is usually not more than 25% to 30% because of friction heat losses both of them none of them
29 On the exaust stroke, the outlet values opens. The residual gases are expelled and piston moves outwards inwards in either way none of these
30 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
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