ECAT Pre General Science Online Test With Answers

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ECAT Pre General Science Online Test

Sr. # Questions Answers Choice
1 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
2 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
3 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
4 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
5 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>
6 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
7 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
8 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>
9 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
10 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
11 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
12 At ordinary temperature, an increase in temperature increases the conductivity of Conductor Semiconductor Insulator Alloy
13 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
14 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
15 Specific resistance of a wire depends upon Length Cross-section area Mass None
16 Cause of heat production in a current carrying conductor is Collisions of free electrons with one another High drift speed of free electrons Collisions of free electrons with atoms or ions of conductor High resistance value
17 In a building, there are 15 bulbs of 40 watts, 5 bulbs of 100 watts, 5 fans of 80 watts and a heater of 1 kilowatt. The voltage of the electric main is 220 volts. The minimum efficiency of the main fuse of the building will be 0.4 A 11.4 A 9.8 A 10.6 A
18 The powers of tow electric bulbs are 100 W and 200 W. Both of them are joined with 220 V mains. The ratio of resistances of their filaments will be 1 : 2 2 : 1 1 : 4 4 : 1
19 A 10 F capacitor is charged to a potential difference of 50 V and is connected to another uncharged capacitor in parallel. Now the common potential difference becomes 20 volt.The capacitance of second capacitor 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, 224);">μ</span>F 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, 224);">μ</span>F 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, 224);">μ</span>F 15<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, 224);">μ</span>F
20 A certain charge liberates 0.8 g of oxygen. The same charge will liberate. how many g of silver? 108 g 10.8 g 0.8 g 108/0.8 g
21 In a voltmeter the conduction takes place due to Electrons only Holes only Electrons and holes Electrons and ions
22 A conducting wire is drawn to double its length. Final resistivity of the material will be Double of the original one Half of the original one One fourth of the original one Same as original one
23 A piece of fuse wire melts when a current of 15 ampere flows through it. With this current. If it dissipates 22.5 W, the resistance of fuse wire will be Zero 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> 1<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> 0.10<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>
24 If 2.2 kilowatt power is transmitted through a 10 ohm line at 22000 volt, the power loss in the form of heat will be 0.1 watt 1 watt 10 watt 100 watt
25 The conductivity of a superconductor is Infinite Very large Very small Zero
26 If 2.2 kilowatt power is transmitted through 1 10 ohm line at 22000 volt, the power loss in the form of heat will be 0.1 watt 1 watt 10 watt 100 watt
27 A 50 volt battery is connected across 10 ohm resistor. The current is 4.5 A. The internal resistance of the battery is Zero 0.5<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> 1.1<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> 5.0<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>
28 A (100 W , 200 W) bulb is connected to a 160 V power supply. The power consumption would be 64 W 80 W 100 W 125 W
29 A wire of radius r has resistance R. If it is stretched to a wire of r/2 radius, then the resistance becomes 2R 4R 16R Zero
30 Two electric bulbs of 200 W and 100 W have same voltage. If R1and R2be their resistance respectively then R<sub>1</sub>= 2R<sub>2</sub> R<sub>2</sub>= 2R<sub>1</sub> R<sub>2 </sub>=<sub> </sub>4R<sub>1</sub> R<sub>1</sub>= 4R<sub>2</sub>
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