GreenHallAcademy
TestSession~2020 TotalMarks:25
Name:
Class:2ndyear
Date:07-January-2019
Test:Physics
Chapter:12(Electrostatics(2
ndHalf))
TimeAllowed:50minutes
MultipleChoiceQuestions(MCQ's).
Q1.Encircleortickthecorrectanswer. (1×5=5)
(i).Thenumberofelectronsinonecoulombchargeis:
(a)6.2×10
18 (b)1.6×10
-19 (c)6.2×10
21 (d)1.6×10
-27
(ii).ThechargeonanelectronwasmeasuredbyMillikanin:
(a)1880 (b)1789 (c)1909 (d)1921
(iii).Theunitofcapacitanceis:
(a)coulomb (b)farad (c)joule (d)watt
(iv).Adielectricmaterialisplacedbetweenplatesofaparallelplatecapacitor.It'scapacitanceincreasesdueto:
(a)electricpolarization (b)electrification (c)ionization (d)electrolysis
(v).IntimeconstantofRCcircuit,howmuchchargeisstoredoutofmaximumchargeq
₀
:
(a)0.37q
₀(b)0.51q
₀(c)0.63q
₀(d)0.90q
₀
Q2.WriteShortanswerstoanyfive(5)questions. (2×5=10)
(i).Acapacitorof6μFisconnectedtoapotentialdifferenceofonevolt.Findtheenergystoredinthecapacitor.
(ii).Definedielectricconstant.Giveitsmathematicalform.
(iii).Defineelectronvolt.Showthat1eV=1.6×10
-19
J.
(iv).Definetimeconstantandgiveitsformula.
(v).Defineunitofcapacitance.
(vi).Doelectronstendtogotoregionofhighpotentialoroflowpotential?
(vii).Writetwosimilaritiesandtwodissimilaritiesbetweenelectricforceandgravitationalforce.
Note:AttemptanyOne(1)longquestion. (5+5=10)
Q3.(a)FindchargeonanelectronbyMillikan'smethod.
(b)Aprotonplacedinauniformelectricfieldof5000N/Cdirectedtoright,isallowedtogoto
adistanceof10.0cmfrompointAtothepointB.Calculate:
(i)workdonebythefield (ii)itsvelocity.
Q4.(a)Whatiscapacitor?Showthatenergydensityforacapacitorwhichhaselectricfieldstrength
Eisgivenby1ε
r
ε
o
E
2
.
2
(b)Acapacitorhasacapacitanceof2.5×10
-8F.Inthechargingprocess,electronsareremoved
fromoneplateandplacedontheotherone.Whenthepotentialdifferencebetweentheplates
is450V,howmanyelectronshavebeentransferred?
