ECAT Physics Online Test With Answers

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ECAT Physics Online Test

Sr. # Questions Answers Choice
1 The speed of a pendulum is measured to be 3.0 s in the inertial reference frame of the pendulum. What is its period measured by an observer moving at a speed of 0.95 c with respect to the pendulum 2.9 s 3.0 s 6.6 s 9.6 s
2 According to the special theory of relativity, time is absolute quantity not absolute quantity constant quantity none of these
3 The special theory of relativity is based on the one postulate two postulates three postulates four postulates
4 The general theory of relativity treats problems involving inertial frame of references accelerating frame of references both of these none of these
5 The special theory of relativity treats problems invoving inertial frame of references accelerating frame of references both of these none of these
6 A non-inertial frame of reference is one, in which law of inertial is valid all laws of physics are the same in all frames a>0 or a<0 a=0
7 An inertial frame is that frame in which a>0 a=0 a<0 none of these
8 Which of the following is not an example of intertial frame a body placed on the surface of earth a body placed in a car moving with uniform velocity a body placed in a car moving with same acceleration none of these
9 An intertial frame of reference is a frame of reference which is at rest moving with uniform velocity either at rest or moving with uniform velocity none of these
10 Absolute motion cannot be detected in its own frame of references in a different frame of references both in its frame and different frame of references none of these
11 The concept of direction and position are purely absolute relative absolute or relative none of these
12 Electron gun consist of three anodes heating cathode three anodes three anodes , heating cathode, grid
13 A beam of electrons is provided by an electron gun Suppray Injection None of these
14 Flurescent screen is a screen where visible spot vanishes is made becomes small and large none of these
15 The CRO deflects the beam of electrons, when they passes through uniform electric field gravitational field magnetic flax magnetic field
16 CRO deflects the beam of proton a-particle electron neutron
17 (CRO) Cathode ray oscilloscope is a device used for high speed velocity graph plotting time-velocity none of these
18 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
19 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
20 A charged particle moving at right angle to the magnetic field will experience minimum force maximum force zero moderate force
21 When charged particle is projected perpendicular to a uniform magnetic field its trajectory is circular elliptical cycloid straight line
22 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>
23 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
24 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
25 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
26 In the expression of force experienced by electron, the direction of both v and B are parallel zero perpendicular none of them
27 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
28 Lorentz force is defined as q(E + V x B) q(E x B + V) q(E x V + B) q(E x B)
29 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
30 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)
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