The correct expression for the potential at a point distance r from a charge q in an electric field is?
A
_q2
4πεor2
B
_q2
4πεor
C
_q
4πεor2
D\(\frac{q}{4πε_or}\)
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Question 832
jamb2011
The diagram above show the positions of a cone. The position which can be described as neutral equilibrium is represented as
AZ only
BX only
CY and Z
DY and X
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Question 833
jamb2011
The diagram above shows two vectors at right angles to each other. The value of the resultant vector is
A14.0 N
B10.0 N
C12.0 N
D13.0 N
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Question 834
jamb2011
Which of the following will be applied when a metal Y is used to electroplate another metal X in electrolysis?
AX is the anode and very high current is used
BX is the anode and Y is the cathode
CY is the cathode and X is the anode
DY is the anode and very high current is used
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Question 835
jamb2011
If the threshold frequency for tungsten is 1.3 x 1015Hz, what is its work function?
[H = 6.6 x 10-34 Js]
A8.58 x 10-19 J
B8.50 x 10-15 J
C8.58 x 10-17 J
D8.85 x 10-18
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Question 836
jamb2011
The electrical properties of germanium can be altered drastically by the addition of impurity. This process is referred to as
Asaturation
Bbonding
Camplification
Ddopping
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Question 837
jamb2011
A radioactive isotope has a decay constant of 10-5s4. Calculate half life
A6.93 x 10-5s
B6.93 x 105s
C6.93 x104s
D6.93 x 10-4s
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Question 838
jamb2011
The bond between silicon and germanium is
Acovalent
Bionic
Cdative
Delectrovalent
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Question 839
jamb2011
Which of the following materials has an increase in resistance with temperature?
Awater
Bmetals
Cwood
Delectrolyte
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Question 840
jamb2011
Two inductors of inductance 4 II and 8 II are arrange in series and a current of 10 A is passed through them. What is the energy stored in them?
A600 J
B50 J
C133 J
D250 J
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Question 841
jamb2011
Under which of the following conditions do gases conduct electricity?
ALow presssure and low p.d
Blow pressure and high p.d
Chigh pressure an low p.d
Dhigh pressure and high p.d
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Question 842
jamb2011
If the charge of electricity is K wh is N4, what is the cost of operating an electrical appliance rated 250 v,2 A for six hours?
AN28
BN12
CN16
DN24
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Question 843
jamb2011
In measuring high frequency a.c, the instrument used is the
Ad.c ammeter
Bmoving coil ammeter
Cmoving iron ammeter
Dhot wire ammeter
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Question 844
jamb2011
Which of the following is a property of steel?
Ait cannot retain its magnetism longer than iron
Bit can be used for making temporary magnets
Cit can be used for making permanent magnets
Dit can easily be magnetized and demagnetized
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Question 845
jamb2011
The eclipse of the sun occurs when the
Amoon is between the sun and the earth
Bearth is between the sun and the moon
Cmoon is not completely hidden in the earth's shadow
Dmoon's umbra falls on some part of the earth
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Question 846
jamb2011
A certain far - sighted person cannot see object that are closer to the eye than 50 cm clearly. Determine the power of the converging lens which will enable him to see at 25 cm
A0.06 D
B0.02 D
C0.03 D
D0.04 D
Eno option is correct
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Question 847
jamb2011
The capacitance of a parallel plate capacitor is 20 μf in air and 60 μf in the presence of a dielectric. What is the dielectric constant?
A0.3
B6.0
C3.0
D2.0
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Question 848
jamb2011
When a red rose flower is observed in blue light, what colour does the observer see?
ARed
BBlue
CMagenta
Dyellow
ENo correct option
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Question 849
jamb2011
When the human eye loses its power of accomodation, the defect is known as
Ashort sightedness
Bpresbyopia
Castigmatism
Dlong sightedness
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Question 850
jamb2011
Three similar cells each of e.m.f 2 v and internal resistance 2Ω are connected in parallel, the total e.m.f and total internal resistance are respectively
