Download QUIZ LEVEL 1 1.Electrical charge interaction can be summarized by

QUIZ
LEVEL 1
1.Electrical charge interaction can be summarized by ___
A)- charge repels other – charge
B)+ charge repels other + charge
C)- charge and + charge attract each other
D)All of these
Ans:D
2. Consider two point charges that are separated by a distance, 2r. If this distance between them is
increased to 5 r, the force between the charges is ___
A)1/25 as great as it had been
B)4/25 as great as it had been
C)1/9 as great as it had been
D)25 times as great as it had been
Ans:B
3. Consider three identical metal spheres that are mounted on insulating stands. Sphere X is neutral,
sphere Y has a charge -1q, and sphere Z has a charge +4q. X and Y are touched together and then
separated ___
A)Each is now charged, with a charge -0.5 q
B)Each is now charged, with a charge -1 q
C)Sphere X is neutral, sphere Y has a charge -1q
neutral
D)Sphere X has charge -1 q, sphere Y is now
Ans:A
4. Consider the electric force between a pair of charged particles a certain distance apart. By
Coulomb'sLaw: if the charge on one of the particles is doubled, the force is ___
A)unchanged
B)halved
C)double
D)quadrupled
Ans:C
5. Point charges Q1 = 1 nC and Q2 = 2 nC are at a distance apart. Which of the following statements are
incorrect? ____
A)The force on Q1 is repulsive.
B)The force on Q2 is the same in magnitude as that on Qx.
C)As the distance between them decreases, the force on Q1 increases linearly.
D)The force on Q2 is along the line joining them.
Ans:C
6. The electric field is zero ___
A)is always zero inside the conductor
C)Never
B)inside any conductor with a static charge.
D)inside conductor provided no voltage drop exists
across it.
Ans:D
7.Positive charge +Q is uniformly distributed on the upper half a rod and a negative charge -Q is
uniformly distributed on the lower half. It is placed along X- axis with its center at origin. What is the
direction of the electric field at point P, on the perpendicular bisector of the rod ___
A)- Y-axis
B)+ Y-axis
C)+ X-axis
D)- X-axis
Ans:C
8.Two point charges, q1 and q2, are placed a distance r apart. The electric field is zero at a point P
between the charges on the line segment connecting them. We conclude that ___
A)q1 and q2 must have the same magnitude and sign
B)P must be midway between q1 and q2
C)q1 and q2 must have opposite signs and may have different magnitudes
D)q1 and q2 must have equal magnitudes and opposite signs
Ans:A
9.Which of the following represents a symmetric E field surface for uniformly distributed line charge:
A)cone
B)reactangular box which is cut by charge symmetrically
C)cylinder
D)sphere
Ans: C
10.Electric potential is
A) Vector
B) Scalar
C) Cannot be said
Ans:B
LEVEL 2
1.What is the force between two small charged spheres having charges of 2 × 10–7C and 3 × 10–7C placed
30 cm apart in air?
Ans:A
A) 6 *10-3 ,Repulsive
B) 6 *10-3 ,attractive
C) 8 *10-3 ,Repulsive
D) 8 *10-3 ,attractive
2. The electrostatic force on a small sphere of charge 0.4 uC due to another small sphere of charge – 0.8
uC in air is 0.2 N. What is the distance between the two spheres?
A) 12 m
B) 12 cm
C)120 m
D) 1.2 cm
3 In Question 2,What is the force on the second sphere due to the first? Ans:B
A)2N
B) 0.2 N
C)20N
D)None
4. Four point charges qA = 2 μC, qB = –5 μC, qC = 2 μC, and qD = –5 μC are located at the corners of a
square ABCD of side 10 cm. What is the force on a charge of 1 μC placed at the centre of the Square?
Ans:D
A)5N
B)10N
C)4N
D)Zero
5. Two point charges qA = 3 μC and qB = –3 μC are located 20 cm apart in vacuum. What is the electric
field at the midpoint O of the line AB joining the two charges?Ans:B
A) 8.1 * 106 NC-1 along OB
B)5.4 * 106 NC-1 along OB
C) 5.4 * 106 NC-1 along OA
D) 8.1 * 106 NC-1 along OA
6. In question 5, If a negative test charge of magnitude 1.5 × 10–9 C is placed at this point, what is the
force experienced by the test charge?Ans:D
A) 8.1 * 106 NC-1 along OB
B)5.4 * 106 NC-1 along OB
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C) 5.4 * 10 NC along OA
D) 8.1 * 106 NC-1 along OA
7. A system has two charges qA = 2.5 × 10–7 C and qB = –2.5 × 10–7 C located at points A: (0, 0, –15 cm)
and B: (0,0, +15 cm), respectively. What are the total charge?Ans:D
A) 5 × 10–7 C
B) = -2.5 × 10–7 C
C) - 5 × 10–7 C
D) zero
8.In Question 7 , What is electric dipole moment of the system ? Ans:A
A) 7.5 × 10–-8 C along z-axis
B) 7.5 × 10–7 C along z-axis
C) 7.5 × 10-8 C along x-axis
D) 7.5 × 10–7 C along x-axis
9. A point charge +10 μC is a distance 5 cm directly above the centre of a square of side 10 cm. What is
the magnitude of the electric flux through the square? Ans:D
A) -2.2 × 105 N m2/C
B) -2.2 × 106 N m2/C
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C) 2.2 × 10 N m /C
D) 2.2 × 105 N m2/C
10. An infinite line charge produces a field of 9 × 104 N/C at a distance of 2 cm. Calculate the linear
charge density.Ans:A
A) 10 μC/m
B) 20 μC/m
C) 40 μC/m
D) 80 μC/m
LEVEL 3
1.How many electrons are contained in 2 coulomb of charge? Ans:D
A) 6.25 *1018 electrons
B) 12.5 *1018 electrons
C) 1.6 *10-19 electrons
D)None
2.Choose the correct option.Ans:C
a) Field lines are continuous curves without any breaks.
b)Two field lines cannot cross each other.
A)a
B)b
C) a&b
D)None
3.Choose the correct option.Ans:A
A) Electrostatic field lines start at positive charges
B)They form closed loops.
A)a
B)b
C) a&b
D)None
4. The electric flux density on a spherical surface r = b is the same for a point charge Q located at the
origin and for charge Q uniformly distributed on surface r = a(a < b).Ans:A
A)Yes
B)No
C)depends on Q
D) Not necessary
5. By saying that the electrostatic field is conservative, we do not mean that
(A) It is the gradient of a scalar potential.
(B) Its circulation is identically zero.
(C) Its curl is identically zero.
(D) The potential difference between any two points is zero.
Ans:D