ECAT Pre General Science Online Test With Answers

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ECAT Pre General Science Online Test

Sr. # Questions Answers Choice
1 If a charged spherical conductor of radius 10 cm has potential V at a point distance 5 cm from its centre, then the potential at a point distance 15 cm from the centre will be 1/3 V 2/3 V 3/2 V 3V
2 Equal charges are given to two spheres of different radii. The potential will Be more on the smaller sphere Be more on the bigger sphere Be equal on both the sphere Depend on the nature of the material of the sphere
3 An electron of charge e coulomb passes through a potential difference of V volts its energy in joules will be V/e eV e/V V
4 The electric field due to an infinite long thin wire at a distance R varies as 1/R 1/R<sup>2</sup> R R<sup>2</sup>
5 A wire is bent into a ring of radius R is given a charge q. The magnitude of the electrical field at the centre of the ring is Two 1/2 Zero 3/2
6 The excess (equal in number) of electrons that must be placed on each of two small spheres spaced 3 cm apart, with force of repulsion between the spheres to be 10-19N, is 25 225 625 1250
7 Two point charges A and B separated by a distance R attract each other with a force of 12 x 10-3N. The force between A and B when the charges on them are doubled and distance is halved 1.92 N 19.2 N 12 N 0.192 N
8 A charge Q is divided into two parts q and Q - q and separated by a distance R. The force of repulsion between them will be maximum when q = Q/4 q = Q/2 q = ! None of these
9 The force of repulsion between two point charges is F, when these are at a distance 0.1 m apart. Now the point charges are replaced by sphere of radii 5 cm each having the same charge as that of the respective point charges. The distance between their centre is again kept 0.1 m ; then the force of repulsion will Increase Decrease Remain F Become 10F/9
10 A point charge Q is placed at the mid-point of a line joining two charges. 4q and q. if the net force on charge q is zero. then Q must be equal to -q +q -2q +4q
11 A point charge A of charge +4μC and another B of charge -1μC are placed in air at a distance 1 m apart. Then the distance of the point on the line joining the charge B, where the resultant electric field is zero, is (in m) 2 1 0.5 1.5
12 A hollow insulated conduction sphere is given a positive charge of 10μC. What will be the electric field at the centre of the sphere if its radius is 2 meters? Zero 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>μ</b></span>C m<sup>-2</sup> 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>μ</b></span>C m<sup>-2</sup> 8<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>μ</b></span>C m<sup>-2</sup>
13 An electric dipole is at the centre of a hollow sphere of radius r. The total normal electric flux through the sphere is (here Q is the charge and d is the distance between the two charges of the dipole) Q/4<i style="box-sizing: border-box; color: rgb(34, 34, 34); font-family: &quot;Times New Roman&quot;; font-size: 18px; background-color: rgb(255, 255, 248);">π</i>r<sup>2</sup> 2Q/4<i style="box-sizing: border-box; color: rgb(34, 34, 34); font-family: &quot;Times New Roman&quot;; font-size: 18px; background-color: rgb(255, 255, 248);">π</i>r<sup>2</sup> Q.d Zero
14 Consider a spherical shell of metal at he centre of which a positive point charge is kept The electric filed is zero outside the shell The electric field is zero everywhere The electric field is zero in the region inside the shell The electric field is non-zero in both regions outside and inside the shell
15 The unit of intensity of electric field is newton/coluomb jule/coluomb volt x metre newton/metre
16 In a Milikian's oil drop experiment the charge on an oil drop is calculated to be 6.35 x 10-19C. The number of excess electrons on the drop is 3.9 4 4.2 6
17 Two point charge +3μC and +8μC repel each other with a force of 40 N. If a charge of -5μC is added to each of them, then the force between then will become -10 N +10 N +20 N -20 N
18 The force between two chares 0.06 m apart is 5 N. If each charge is moved towards the other by 0.01 m, then the force between them will become 7.20 N 11.25 N 22.50 N 45.00
19 A gas is compressed adiabatically till its temperature is double. The ratio of its final volume to initial volume will be 1/2 More than 1/2 Less than 1/2 Between 1 and 2
20 First law of thermodynamics is consequence of conservation of Work Energy Heat All of these
21 At what temperature the adiabatic change is equivalent to the isothermal change? Zero degree Celsius Zero Kelvin Critical temperature Above critical temperature
22 First law of thermodynamic is special case of Law of conservation of energy Charle's law Law of conservation of mass Boyle's law
23 Two samples A and B of a gas initially of the same temperature and pressure are compressed from a volume V to a volume V/2 such that A is compressed isothermally and B adiabatically. The final pressure A greater than than of B A is equal to that of B A is less than that of B A is twice the pressure of B
24 Rice takes longest to cook In a submarine 100 m below the surface of the sea At sea level At Murree At Mount Everest
25 Melting point of ice Increases with increasing pressure Decreases with increasing pressure Is independent of pressure Is proportional to pressure
26 An amount of water of mass 20 g at 0°C is mixed with 40 g of water at 10°C. Final temperature of mixture is -20<span style="color: rgb(84, 84, 84); font-family: arial, sans-serif; font-size: small;">°C</span> 6.67<span style="color: rgb(84, 84, 84); font-family: arial, sans-serif; font-size: small;">°C</span> 5<span style="color: rgb(84, 84, 84); font-family: arial, sans-serif; font-size: small;">°C</span> 0<span style="color: rgb(84, 84, 84); font-family: arial, sans-serif; font-size: small;">°C</span>
27 Specific heat at constant pressure is greater than the specific heat at constant volume because Heat is used up to increase temperature at constant pressure Heat is used by gas for expansions purposes at constant pressure Heat is use dup to increase internal energy The above statement is invalid
28 If water in a closed bottle is taken up to the moon and opened, the water gets Freeze Boiled Dissociated into O<sub>2</sub>and H<sub>2</sub> Evaporated
29 What temperature is the same on Celsius scale as well as on Fahrenheit scale? 32<span style="color: rgb(84, 84, 84); font-family: arial, sans-serif; font-size: small;">°C</span> -32<span style="color: rgb(84, 84, 84); font-family: arial, sans-serif; font-size: small;">°C</span> -40<span style="color: rgb(84, 84, 84); font-family: arial, sans-serif; font-size: small;">°C</span> -212<span style="color: rgb(84, 84, 84); font-family: arial, sans-serif; font-size: small;">°C</span>
30 Amount of heat required to raise the temperature of a body through 1 K is called its Specific heat Water equivalent Thermal capacity Entropy
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