ECAT Pre General Science Physics Chapter 14 Electromagnetism Online Test With Answers

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ECAT Pre General Science Physics Chapter 14 Electromagnetism Online Test

Sr. # Questions Answers Choice
1 The voltage increases linearly with time velocity acceleration torque
2 How many number of anodes used in electron gun one two three six
3 Electron gun consist of three anodes heating cathode three anodes three anodes , heating cathode, grid
4 A beam of electrons is provided by an electron gun Suppray Injection None of these
5 Flurescent screen is a screen where visible spot vanishes is made becomes small and large none of these
6 The CRO deflects the beam of electrons, when they passes through uniform electric field gravitational field magnetic flax magnetic field
7 CRO deflects the beam of proton a-particle electron neutron
8 (CRO) Cathode ray oscilloscope is a device used for high speed velocity graph plotting time-velocity none of these
9 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
10 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
11 A charged particle moving at right angle to the magnetic field will experience minimum force maximum force zero moderate force
12 When charged particle is projected perpendicular to a uniform magnetic field its trajectory is circular elliptical cycloid straight line
13 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>
14 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
15 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
16 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
17 In the expression of force experienced by electron, the direction of both v and B are parallel zero perpendicular none of them
18 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
19 Lorentz force is defined as q(E + V x B) q(E x B + V) q(E x V + B) q(E x B)
20 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
21 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)
22 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
23 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
24 When current passes through a solenoid coil, it behaves like a loop circle bar magnet none of these
25 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
26 The magnetic field outside the solenoid due to current is strong zero weak uniform
27 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
28 The magnetic field in the middle of a solenoid due to current is weak strong and uniform none-uniform zero
29 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
30 Tesla is the unit of Magnetic induction or flux density Magnetic flux Self inductance None of these
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