ECAT Pre General Science Online Test With Answers

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ECAT Pre General Science Online Test

Sr. # Questions Answers Choice
1 Flurescent screen is a screen where visible spot vanishes is made becomes small and large none of these
2 The CRO deflects the beam of electrons, when they passes through uniform electric field gravitational field magnetic flax magnetic field
3 CRO deflects the beam of proton a-particle electron neutron
4 (CRO) Cathode ray oscilloscope is a device used for high speed velocity graph plotting time-velocity none of these
5 A magnetic force on an electron travelling with 108ms-1parallel to a field of strength 1 Wb m-2is Zero 10<sup>5 </sup>m 10<sup>-10</sup>N 10<sup>8</sup>N
6 The magnetic force exerted on an electron moving with velocity 'v' at right angle to the magnetic field is given by F=eVB F=e<sup>2</sup>V/B F=e/VB F=B<sup>2</sup>/ev
7 A charged particle moving at right angle to the magnetic field will experience minimum force maximum force zero moderate force
8 When charged particle is projected perpendicular to a uniform magnetic field its trajectory is circular elliptical cycloid straight line
9 Charge to mass ratio (e/m) of an electron is given by the relation e/m = 2V/Br<sup>2</sup> e/m = 2V/B<sup>2</sup>r e/m = 2V/B<sup>2</sup>r<sup>2</sup> e/m = V/2B<sup>2</sup>r<sup>2</sup>
10 The e/m of an electron moving in a circular path in a magnetic field is equal to V/Br V/B<sup>2</sup>r<sup>2</sup> V<sup>2</sup>/Br<sup>2</sup> V<sup>2</sup>/Br
11 Centripetal force for electron is given by mv<sup>2</sup>/ r mv / r<sup>2</sup> mv<sup>2</sup>/ r mr<sup>2</sup>/ v
12 When an electron enters in a magnetic field right angle to its motion, the magnitude of its velocity will be changed zero unchanged none of these
13 In the expression of force experienced by electron, the direction of both v and B are parallel zero perpendicular none of them
14 If volume of wire is 'AL' and there are 'n' numbers of charge carriers per unit volume, then the total number of charge carriers are n/AL Al/n nAL nA/L
15 Lorentz force is defined as q(E + V x B) q(E x B + V) q(E x V + B) q(E x B)
16 The force experienced by charged particle is maximum, if it moves parallel to magnetic field perpendicular to magnetic field opposite to the magnetic field none of these
17 41 The force experience, when proton projected in a magnetic field with velocity 'v' is +e(v x B) -C(V x B) +e<sup>2</sup>(v x B) -e(v<sup>2</sup>x B)
18 The force experienced by an electron projected in a magnetic field B with a velocity V is given by F=e(V x B) F= -e(V x B) F= e(B x V) Both a and c
19 The force experienced by a single charge carrier moving with velocity 'v' i magnetic field of strength 'B' is given by F =q(v/B) F=q<sup>2</sup>(v x B) F=q(v x B) F= vx B
20 When current passes through a solenoid coil, it behaves like a loop circle bar magnet none of these
21 The strength of magnetic field around the current conductor is Smaller near the conductor Greater near the conductor Greater at the large distance from the conductor Constant near and away from the conductor
22 The magnetic field outside the solenoid due to current is strong zero weak uniform
23 Which one of the following relations is correct? 1 Wb-m<sup>2</sup>= Nm<sup>-1</sup>A<sup>-1</sup> 1 tesla = 104 gausses 1 Wb-m<sup>2</sup>= 1 tesla All of the above
24 The magnetic field in the middle of a solenoid due to current is weak strong and uniform none-uniform zero
25 The SI unit of magnetic permeability is WB A<sup>-1</sup>m<sup>-1</sup> WB mA<sup>-1</sup> WB Am<sup>-1</sup> None of these
26 Tesla is the unit of Magnetic induction or flux density Magnetic flux Self inductance None of these
27 The SI unit of flux density is. Tesla Weber Gaun Weber/meter
28 The unit of flux density is also given by Weber/m<sup>2</sup>or Wb . m<sup>-2</sup> Weber/mor Wb . m Weber/mor Wb . m<sup>-1</sup> Weber or Wb
29 The SI unit of flux density is Newton/Amp-meter Newton-m/Ampere Newton-m/Amp<sup>2</sup> Newton-Amp/meter
30 The straight current carrying conductor experiences maximum force in a uniform magnetic field when it is placed parallel to the field Perpendicular to the field At an angle of 45 to the field None of the above
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