Physics ECAT Pre Engineering MCQ's Test For Full Book With Answers

Physics ECAT Pre Engineering MCQ's Test For Full Book

Sr. # Questions Answers Choice
1 A capacitor acts as an infinite resistance for AC DC Both AC and DC Neither AC nor DC
2 A 220 V, 50 Hz. A.C. source is connected to an inductance of 0.2 H and a resistance of 20 ohm in series. What is the current in the circuit? 10 A 5 A 33.3 A 3.33 A
3 In an A.C. circuit, a resistance of R ohm is connected in series with an inductance L. If phase angle between voltage and current be 45°. the value of inductive reactance will be R/4 R/2 R Cannot be found with the given data
4 In L.C.R series A.C. circuit, the phase angle between current and voltage is Any angle between 0 and <u>+</u><i style="box-sizing: border-box; color: rgb(34, 34, 34); font-family: &quot;Times New Roman&quot;; font-size: 19.8px;">π</i><span style="box-sizing: border-box; color: rgb(34, 34, 34); font-family: &quot;Times New Roman&quot;; font-size: 19.8px;">/2</span> <i style="box-sizing: border-box; color: rgb(34, 34, 34); font-family: &quot;Times New Roman&quot;; font-size: 19.8px;">π</i><span style="box-sizing: border-box; color: rgb(34, 34, 34); font-family: &quot;Times New Roman&quot;; font-size: 19.8px;">/2</span> <i style="box-sizing: border-box; color: rgb(34, 34, 34); font-family: &quot;Times New Roman&quot;; font-size: 19.8px;">π</i> Any angle between 0 and<i style="font-family: &quot;Times New Roman&quot;; font-size: 19.8px; color: rgb(34, 34, 34); box-sizing: border-box;">π</i><span style="font-family: &quot;Times New Roman&quot;; font-size: 19.8px; color: rgb(34, 34, 34); box-sizing: border-box;">/2</span>
5 Thermocouple is an arrangement of two different metals To convert heat energy in to electrical energy To produce more heat To convert heat energy into chemical energy To convert electric energy in to heat energy
6 Current provided by a battery is maximum when Internal resistance equal to external resistance Internal resistance is greater than external resistance Internal resistance is less then external resistance None of these
7 The thermistors are usually made of Metals with low temperature coefficient of resistivity Metals with high temperature coefficient of resistivity Metal oxides with high temperature coefficient of resistivity Semi conducting materials having low temperature coefficient of resistivity
8 In Pakistan electricity is supplied for domestic use at 220 V, it is supplied at 110 V in USA. If the resistance of a 60 W bulb for use in Pakistan is R, the resistance of a 60 W bulb for use in USA will be 2 R R/4 R/2 R
9 When three identical bulbs of 60 watt, 200 volt rating are connected in series to a 200 volt supply, the power drawn by them will be 180 watt 10 watt 20 watt 60 watt
10 Which of the following does not obey ohm's law? Copper Al Diode None
11 Battery is charged in motor cars, which is based on Chemical effect Magnetic effect Electric effect None
12 The minimum resistance that can be obtained by connecting 5 resistance of 1/4Ωeach is 4/5<span style="color: rgb(34, 34, 34); font-family: &quot;Times New Roman&quot;; font-size: 24px; text-align: center; background-color: rgb(255, 255, 248);"><b>Ω</b></span> 5/4<span style="color: rgb(34, 34, 34); font-family: &quot;Times New Roman&quot;; font-size: 24px; text-align: center; background-color: rgb(255, 255, 248);"><b>Ω</b></span> 20<span style="color: rgb(34, 34, 34); font-family: &quot;Times New Roman&quot;; font-size: 24px; text-align: center; background-color: rgb(255, 255, 248);"><b>Ω</b></span> 0.05 <span style="color: rgb(34, 34, 34); font-family: &quot;Times New Roman&quot;; font-size: 24px; text-align: center; background-color: rgb(255, 255, 248);"><b>Ω</b></span>
13 The resistance of an incandescent lamp is Smaller when switched on Greater when switched off The same whether it is switch off or switch on Greater when switched on
14 A current of 1.6 A is passed through a solution of CuSO4. How many Cu2+ions are liberated in one minute? 3 x 10<sup>20</sup> 3 x 10<sup>10</sup> 6 x 10<sup>20</sup> 6 x 10<sup>10</sup>
15 A heater coil rated at (1000 W - 200 V) is connected to 110 volt line. What will be the power consumed? 200 W 302.5 250 W 350 W
16 The colour sequence in a carbon resistor in red, brown, orange and silver. The resistance of the resistor is 21 x 10<sup>3</sup><u>+</u> 10% 23 x 10<sup>1</sup><u>+</u> 10% 21 x 10<sup>3</sup><u>+</u> 5% 12 x 10<sup>3</sup><u>+</u> 5%
17 For two resistance wires joined in parallel, the resultant resistance is 6/5 ohm. When one of the resistance wire breaks, the effective resistance becomes 2 ohm. The resistance of the broken wire is 3/5 ohm 2 ohm 6/5 ohm 3 ohm
18 A uniform resistance wire of Length L and diameter d has a resistance R. Another wire of same material has length, 4L and diameter 2d, the resistance will be 2 R R R/2 R/4
19 Calculate the amount of charge flowing in 2 minutes in a wire of resistance 10Ωwhen a potential difference of 20 V is applied between its ends 120 C 240 C 20 C 4 C
20 106electrons are moving through a wire per second, the current developed is 1.6 x 10<sup>-19</sup> 1 A 1.6 x 10<sup>-15 </sup>A 10<sup>6</sup>A
21 The resistance of 20 cm long wire is 10Ω. When the length is changed to 40 cm. The new resistance is 10<span style="color: rgb(34, 34, 34); font-family: &quot;Times New Roman&quot;; font-size: 24px; text-align: center; background-color: rgb(255, 255, 248);"><b>Ω</b></span> 20<span style="color: rgb(34, 34, 34); font-family: &quot;Times New Roman&quot;; font-size: 24px; text-align: center; background-color: rgb(255, 255, 248);"><b>Ω</b></span> 30<span style="color: rgb(34, 34, 34); font-family: &quot;Times New Roman&quot;; font-size: 24px; text-align: center; background-color: rgb(255, 255, 248);"><b>Ω</b></span> 40<span style="color: rgb(34, 34, 34); font-family: &quot;Times New Roman&quot;; font-size: 24px; text-align: center; background-color: rgb(255, 255, 248);"><b>Ω</b></span>
22 If two bulbs one of 60 W and other of 100 W are connected in parallel, then which one of the following will flow more? 60 W bulb 100 W bulb Both equally None of these
23 Which one of the following causes production of heat when current is set up in a wire? Fall of electrons from higher orbits to lower orbits Inter-atomic collisions Inter-electron collisions Collisions of conduction electron with atoms
24 Three resistors of resistance R each are combined in various ways. Which of the following cannot be obtained? 3R<span style="color: rgb(34, 34, 34); font-family: &quot;Times New Roman&quot;; font-size: 24px; text-align: center; background-color: rgb(255, 255, 248);"><b>Ω</b></span> 2R/4<span style="color: rgb(34, 34, 34); font-family: &quot;Times New Roman&quot;; font-size: 24px; text-align: center; background-color: rgb(255, 255, 248);"><b>Ω</b></span> R/3<span style="color: rgb(34, 34, 34); font-family: &quot;Times New Roman&quot;; font-size: 24px; text-align: center; background-color: rgb(255, 255, 248);"><b>Ω</b></span> 2R/3<span style="color: rgb(34, 34, 34); font-family: &quot;Times New Roman&quot;; font-size: 24px; text-align: center; background-color: rgb(255, 255, 248);"><b>Ω</b></span>
25 The resistance of the given conductor can be increased by Increasing the area Changing resistivity Decreasing the length None of the above because change does not matter because in any case the volume remains the same
26 A 100 W, 200 V bulb is connected to a 160 volts supply. The actual power consumption would be 64 W 80 W 100 W 125 W
27 A 60 W bulb operates on 220 V supply. The current flowing through the bulb is 11/3 A 3 A 3/11 A 6
28 At ordinary temperature, an increase in temperature increases the conductivity of Conductor Semiconductor Insulator Alloy
29 Potentiometer is more sensitive than voltmeter, because Voltmeter has a very high resistance Voltmeter has a very low resistance Potentiometer does not draw any current from a source of unknown potential difference Potentiometer is sensitive
30 A car battery has e.m.f 12 volt and internal resistance 5 x 10-2ohm. If it draws 60 ampere current, the terminal voltage of the battery will be 5 volt 3 volt 15 volt 9 volt
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