Electrostatic Forces Question Bank |
1
One of the following charges could be the charge of an object:
\[q=8×10^{-19} \;\;c\;\;\;\;\;\;-C\]
\[q=5.2×10^{-19} \;\;c\;\;\;\;\;\;-A\]
\[q=2×10^{-19} \;\;c\;\;\;\;\;\;-D\]
\[q=3×10^{-19} \;\;c\;\;\;\;\;\;-B\]
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2
A glass rod was rubbed with a piece of wool and became positively charged. This means the rod:
Gained electrons -C
Lost protons -A
Lost electrons -D
Gained protons -B
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3
One of the following conductors had its mass decreased
Note:
(A , B ) show proximity in the image
( C , D ) show contact in the image
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4
(0.5 g) The number of electrons in water is equivalent to
(18) Knowing that the molar mass of water equals
The atomic number of oxygen equals 8 and the atomic number of hydrogen equals 1
\[N=1.67×10^{23}\;\;\;\;\;\;-C\]
electron
\[N=1.67×10^{25} \;\;\;\;\;\;-A\]
electron
\[N=1.67×10^{22}\;\;\;\;\;\;-D\]
electron
\[N=1.67×10^{24}\;\;\;\;\;\;-B\]
electron
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5
Number of electrons in 2 grams of oxygen molecule
\[o_2\]
Given that the atomic mass of oxygen
\[M=16\;g\] and the atomic number equals 8
\[N=6.02×10^{24}\;\;\;\;\;\;-C\]
electron
\[N=6.02×10^{22} \;\;\;\;\;\;-A\]
electron
\[N=6.02×10^{25}\;\;\;\;\;\;-D\]
electron
\[N=6.02×10^{23}\;\;\;\;\;\;-B\]
electron
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6
A neutral electroscope was approached by a positively charged conductor
It was observed that the leaves of the electroscope diverged which means
The knob and leaves were charged with positive charge -C
The knob was charged with positive charge and the leaves with negative charge -A
The knob and leaves were charged with negative charge -D
The knob was charged with negative charge and the leaves with positive charge -B
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7
Two similar neutral conductors were approached by a positively charged object as shown
The conductors were separated from each other without removing the charged object
Then the charge on the conductors
(B positive charge)(A negative charge) -C
(B negative charge) (A negative charge) -A
(B negative charge)(A positive charge) -D
(B positive charge)(A positive charge)-B
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8
Two similar neutral conductors were approached by a negatively charged object as shown
Then connected to ground
and then disconnected from ground
The conductors were separated from each other without removing the charged object
Then the charge on the conductors
(B positive charge)(A neutral) -C
(B negative charge) (A neutral) -A
(B positive charge)(A positive charge) -D
(B negative charge)(A positive charge)-B
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9
Two similar neutral conductors were approached by a positively charged object
as shown in the figure
Then connected to ground
and then disconnected from ground
The charged object was removed
and the conductors were separated from each other
Then the charge on the conductors
(B positive charge)(A neutral) -C
(B negative charge) (A negative charge) -A
(B neutral)(A positive charge) -D
(B negative charge)(A positive charge)-B
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10
(A) Two identical spherical conductors, conductor A was charged
( -3µc ) with a charge of
(B ) Conductor B was charged
(9µc )with a charge of
( A ) The conductors were touched together and then separated
The number of electrons lost by conductor A
equals
\[ 4.43 ×10^{13}\;\;\;\;\;\;-C\]
electron
\[ 3.75 ×10^{13}\;\;\;\;\;\;-A\]
electron
\[5.85 ×10^{13}\;\;\;\;\;\;-D\]
electron
\[1.87 ×10^{13}\;\;\;\;\;\;-B\]
electron
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11
(n) In a semiconductor doped with elements from group 15, it becomes a semiconductor type
capable of conducting current. The carrier responsible for current conduction in the semiconductor at absolute zero temperature
Electrons only -C
Holes and electrons -A
Positive charges only -D
Holes only -B
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12
An electroscope with its base connected to the ground had a negatively charged object brought near it without contact. One of the following figures shows what happens to the electroscope
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13
By what factor does the distance between two charges change if the mutual force between them doubles while keeping other factors constant?
\[r_2=0.25 r\;\;\;\;\;\;-C\]
\[r_2=0.7 r\;\;\;\;\;\;-A\]
\[r_2=2 r\;\;\;\;\;\;-D\]
\[r_2=4 r\;\;\;\;\;\;-B\]
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14
Two point charges with distance
\[r\] between them. The electric force between them was calculated to be
\[F_1=9\;N\]. When the distance between them became
\[3r\] and one of the charges was doubled, the new electric force between them becomes
\[F=3 \;\;N\;\;\;\;\;\;-C\]
\[F=1 \;\;N\;\;\;\;\;\;-A\]
\[F=4 \;\;N\;\;\;\;\;\;-D\]
\[F=2 \;\;N\;\;\;\;\;\;-B\]
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15
Three charges in a straight line as shown in the figure of the same type
with magnitudes shown in the figure. The direction and magnitude of the force acting
on charge
q2
\[F_{net}=0.0\;\;\;\;\;\;-C\]
\[F_{net}=\frac{K.q^2}{2r^2}\;\;\;\;\;\;-A\]
to the right
\[F_{net}=\frac{K.q^2}{4r^2}\;\;\;\;\;\;-D\]
to the right
\[F_{net}=\frac{K.q^2}{2r^2}\;\;\;\;\;\;-B\]
to the left
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16
The force acting on
\[q_1\] was calculated to be 5 Newton
and its direction is shown in the figure
The force acting
from
q3 on q1
equals 3 Newton. Then the second charge's magnitude and type are:
\[q_2= 2.2×10^{-6}\;\;c \;\;\;\;\;\;-C\]
positive
\[q_2= 6.6×10^{-6} \;\;c\;\;\;\;\;\;-A\]
negative
\[q_2= 3.3×10^{-6}\;\;c \;\;\;\;\;\;-D\]
negative
\[q_2= 4.4×10^{-6}\;\;c \;\;\;\;\;\;-B\]
positive
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17
Two point charges, the first with magnitude
\[q_1=- 4\;\;𝜇𝑐\] the second with unknown magnitude and type
\[q_2= ?\] The distance between them
\[r=0.1\;\; m\] An electron was placed between the charges as shown in the figure at a distance
\[r_2= 0.02\;\; m\] from the second charge
It was observed that the electron is balanced. The magnitude and type of the second charge equals:
\[q_2= 2.5×10^{-5}\;\;c \;\;\;\;\;\;-C\]
negative
\[q_2= 3.5×10^{-5} \;\;c\;\;\;\;\;\;-A\]
negative
\[q_2= 6.5×10^{-5}\;\;c \;\;\;\;\;\;-D\]
positive
\[q_2= 5.3×10^{-5}\;\;c \;\;\;\;\;\;-B\]
positive
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18
The figure below shows three point charges in a straight line, all positive. If the total electric force acting on the second charge is zero, then the ratio \[\frac{𝑟_1}{𝑟_2}\] equals:
\[\frac{𝑟_1}{𝑟_2}=0.57\;\;\;\;\;\;-C\]
\[\frac{𝑟_1}{𝑟_2}=0.81\;\;\;\;\;\;-A\]
\[\frac{𝑟_1}{𝑟_2}=1.41\;\;\;\;\;\;-D\]
\[\frac{𝑟_1}{𝑟_2}=1.22\;\;\;\;\;\;-B\]
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19.
Two charges of different types, the first is positive and four times the second which is negative, were placed with the first charge at the origin and the second at a distance of \[10\;\; Cm\] in the direction of the horizontal axis as shown in the figure. At what position should we place a proton so that the net force on it is zero?
\[X=0.2 \;\;m\;\;\;\;\;\;-C\]
\[X=0.14 \;\;m\;\;\;\;\;\;-A\]
\[X=0.16 \;\;m\;\;\;\;\;\;-D\]
\[X=0.04 \;\;m\;\;\;\;\;\;-B\]
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20
Two charged balls with identical charges and equal mass \[m_1=m_2=0.1\;\; Kg\] each were suspended by a non-extensible and massless thread. The balls moved apart due to an electric force such that each thread formed an angle \[𝜃 = 10^0\] with the vertical line. The electric force acting on each ball is:
\[Fe= 0.59\;\; N\;\;\;\;\;\;-C\]
\[Fe= 0.43\;\; N \;\;\;\;\;\;-A\]
\[Fe= 0.17\;\; N\;\;\;\;\;\;-D\]
\[Fe= 0.33\;\; N\;\;\;\;\;\;-B\]
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21
In the figure below, four charges are placed at the corners of a square with side length \[r\]. Their magnitudes are shown in the figure. A charge \[q\] is placed at the center of the square. The direction and magnitude of the net electric force acting on the charge \[q\] at the center of the square is:
\[F_{net}=\frac{8 K.q^2}{r^2}\;\;\;\;\;\;-C\]
Towards q2
\[F_{net}=\frac{12K.q^2}{r^2}\;\;\;\;\;\;-A\]
Towards q1
\[F_{net}=\frac{12K.q^2}{r^2}\;\;\;\;\;\;-D\]
Towards q4
\[F_{net}=\frac{8 K.q^2}{r^2}\;\;\;\;\;\;-B\]
Towards q2
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22
Two charges of the same type, the first is three times the second charge as shown in the figure below. The distance between them is 0.2 m. If the electric force between them is 0.6 N, then the magnitude of each charge is:
\[q_1= 2.28 × 10^{-6}\;\;c\;\;\;\;\;\;\;\;q_1= 9.42 × 10^{-7}\;\;c\;\;\;\;\;\;-C\]
\[q_1= 4.5 × 10^{-6}\;\;c\;\;\;\;\;\;\;\;q_1= 4.5 × 10^{-6}\;\;c\;\;\;\;\;\;-A\]
\[q_1= 1.6 × 10^{-6}\;\;c\;\;\;\;\;\;\;\;q_1= 5.3 × 10^{-7}\;\;c\;\;\;\;\;\;-D\]
\[q_1= 2.8 × 10^{-6}\;\;c\;\;\;\;\;\;\;\;q_1= 1 × 10^{-7}\;\;c\;\;\;\;\;\;-B\]
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23
Three charges with equal magnitudes and types as shown in the figure are placed at the vertices of an equilateral triangle. The direction and magnitude of the force acting on the first charge is equal to:
\[F_{net}=K\frac{2q^2}{r^2}\;\;\;\;\;\;-C\]
Towards East
\[F_{net}=K\frac{q^2}{r^2}\;\;\;\;\;\;-A\]
Towards North
\[F_{net}=K\frac{2q^2}{r^2}\;\;\;\;\;\;-D\]
Towards Northeast
\[F_{net}=K\frac{q^2}{r^2}\;\;\;\;\;\;-B\]
Towards East
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24
Three charges with equal type and magnitude (each \[2q\]) were placed on the circumference of a semicircle as shown in the figure below with equal distances. A charge \[-q\] was placed at the center of the circle. The magnitude and direction of the force acting on the charge at the center of the circle is:
\[F_{net}=K\frac{2q^2}{r^2}\;\;\;\;\;\;-C\]
Towards left
\[F_{net}=K\frac{q^2}{2r^2}\;\;\;\;\;\;-A\]
Towards left
\[F_{net}=K\frac{2q^2}{4r^2}\;\;\;\;\;\;-D\]
Towards northeast
\[F_{net}=K\frac{q^2}{r^2}\;\;\;\;\;\;-B\]
Towards right
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25
Assume that the Earth and the Moon were charged with equal charges in magnitude and type, the amount of charge for each is
\[q_e=q_m=q\] and the distance between them is \[r\]
The electric force became equal to the gravitational force between them.
The Moon and Earth were brought to half the distance between them until the electric force and gravitational force became equal again.
The Earth and Moon must be charged with a charge equal to:
\[q_e=q_m=0.25q\;\;\;\;\;\;-C\]
\[q_e=q_m=0.5q\;\;\;\;\;\;-A\]
\[q_e=q_m=2q\;\;\;\;\;\;-D\]
\[q_e=q_m=q\;\;\;\;\;\;-B\]
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26
Three equal charges in magnitude and type are placed at the vertices of an equilateral triangle (12 N) as shown in the figure below. The force between two charges was calculated to be 12 N. The resultant force acting on any charge equals:
\[F_{net}=10.39 \;\; N\;\;\;\;\;\;-C\]
\[F_{net}=24 \;\; N\;\;\;\;\;\;-A\]
\[F_{net}=20.87 \;\; N\;\;\;\;\;\;-D\]
\[F_{net}=16.65 \;\; N\;\;\;\;\;\;-B\]
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27
Three charges were placed at the vertices of a right-angled triangle as shown in the figure below
The force exerted by the second charge on the first charge was calculated and its components were \[F_{21}=(- 0.4\hat{x} , - 0.3\hat{y} )\]
The force exerted by the third charge on the first charge was calculated and its components were
\[F_{31}=( 0\hat{x} , + 0.6\hat{y} )\] Then one of the following answers matches the previous information and the figure
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28
Two charges of different types where the first is twice the second \[q_1=+2q ,q_2=-q\] If the electric force exerted by the first charge on the second is
\[F_{12}= 10 N \] to the right
then the force exerted by the second charge on the first equals
\[F_{21}=10 \;\;N \;\;\;\;\;\;-C\]
to the left
\[F_{21}=20 \;\;N \;\;\;\;\;\;-A\]
to the right
\[F_{21}=10 \;\;N \;\;\;\;\;\;-D\]
to the right
\[F_{21}=20 \;\;N \;\;\;\;\;\;-B\]
to the left
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29
Two charges with the same magnitude as shown in the figure, the distance
between them is
0.2 m
If the electric force between
them equals
0. 4 N
Then the magnitude of each charge equals
\[q_1=q_2= 1.3 ×10^{-6}\;\;c\;\;\;\;\;\;-C\]
\[q_1=q_2= 1.7 ×10^{-12} \;\;c\;\;\;\;\;\;-A\]
\[q_1=q_2= 8.6 ×10^{-12}\;\;c\;\;\;\;\;\;-D\]
\[q_1=q_2= 3.9 ×10^{-6}\;\;c\;\;\;\;\;\;-B\]
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Answer the following questions
1
In the figure below, four charges are placed at
the corners of a square with side length
\[10\;cm\]
Their magnitudes are
\[q_1=-3\;µ c\;\;\;\;\;\;\;q_2=-2\;µ c\;\;\;\;\;\;\;q_3=+3\;µ c\;\;\;\;\;\;\;q_4=-2\;µ c\]
as shown in the figure below
Calculate the electric force acting on
\[q_1\]
\[.....................................\;\;\;\;............................................\]
\[.....................................\;\;\;\;............................................\]
\[.....................................\;\;\;\;............................................\]
\[.....................................\;\;\;\;............................................\]
\[.....................................\;\;\;\;............................................\]
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One of the following charges could be the charge of an object:
\[q=8×10^{-19} \;\;c\;\;\;\;\;\;-C\] |
\[q=5.2×10^{-19} \;\;c\;\;\;\;\;\;-A\] |
\[q=2×10^{-19} \;\;c\;\;\;\;\;\;-D\] |
\[q=3×10^{-19} \;\;c\;\;\;\;\;\;-B\] |
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A glass rod was rubbed with a piece of wool and became positively charged. This means the rod:
Gained electrons -C |
Lost protons -A |
Lost electrons -D |
Gained protons -B |
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One of the following conductors had its mass decreased
Note:
(A , B ) show proximity in the image
( C , D ) show contact in the image
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(0.5 g) The number of electrons in water is equivalent to
(18) Knowing that the molar mass of water equals
The atomic number of oxygen equals 8 and the atomic number of hydrogen equals 1
\[N=1.67×10^{23}\;\;\;\;\;\;-C\] electron |
\[N=1.67×10^{25} \;\;\;\;\;\;-A\] electron |
\[N=1.67×10^{22}\;\;\;\;\;\;-D\] electron |
\[N=1.67×10^{24}\;\;\;\;\;\;-B\] electron |
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Number of electrons in 2 grams of oxygen molecule
\[o_2\]
Given that the atomic mass of oxygen
\[M=16\;g\] and the atomic number equals 8
\[N=6.02×10^{24}\;\;\;\;\;\;-C\] electron |
\[N=6.02×10^{22} \;\;\;\;\;\;-A\] electron |
\[N=6.02×10^{25}\;\;\;\;\;\;-D\] electron |
\[N=6.02×10^{23}\;\;\;\;\;\;-B\] electron |
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A neutral electroscope was approached by a positively charged conductor
It was observed that the leaves of the electroscope diverged which means
The knob and leaves were charged with positive charge -C |
The knob was charged with positive charge and the leaves with negative charge -A |
The knob and leaves were charged with negative charge -D |
The knob was charged with negative charge and the leaves with positive charge -B |
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Two similar neutral conductors were approached by a positively charged object as shown
The conductors were separated from each other without removing the charged object
Then the charge on the conductors
(B positive charge)(A negative charge) -C |
(B negative charge) (A negative charge) -A |
(B negative charge)(A positive charge) -D |
(B positive charge)(A positive charge)-B |
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Two similar neutral conductors were approached by a negatively charged object as shown
Then connected to ground
and then disconnected from ground
The conductors were separated from each other without removing the charged object
Then the charge on the conductors
(B positive charge)(A neutral) -C |
(B negative charge) (A neutral) -A |
(B positive charge)(A positive charge) -D |
(B negative charge)(A positive charge)-B |
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Two similar neutral conductors were approached by a positively charged object
as shown in the figure
Then connected to ground
and then disconnected from ground
The charged object was removed
and the conductors were separated from each other
Then the charge on the conductors
(B positive charge)(A neutral) -C |
(B negative charge) (A negative charge) -A |
(B neutral)(A positive charge) -D |
(B negative charge)(A positive charge)-B |
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(A) Two identical spherical conductors, conductor A was charged
( -3µc ) with a charge of
(B ) Conductor B was charged
(9µc )with a charge of
( A ) The conductors were touched together and then separated
The number of electrons lost by conductor A
equals
\[ 4.43 ×10^{13}\;\;\;\;\;\;-C\] electron |
\[ 3.75 ×10^{13}\;\;\;\;\;\;-A\] electron |
\[5.85 ×10^{13}\;\;\;\;\;\;-D\] electron |
\[1.87 ×10^{13}\;\;\;\;\;\;-B\] electron |
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(n) In a semiconductor doped with elements from group 15, it becomes a semiconductor type
capable of conducting current. The carrier responsible for current conduction in the semiconductor at absolute zero temperature
Electrons only -C |
Holes and electrons -A |
Positive charges only -D |
Holes only -B |
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An electroscope with its base connected to the ground had a negatively charged object brought near it without contact. One of the following figures shows what happens to the electroscope
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By what factor does the distance between two charges change if the mutual force between them doubles while keeping other factors constant?
\[r_2=0.25 r\;\;\;\;\;\;-C\] |
\[r_2=0.7 r\;\;\;\;\;\;-A\] |
\[r_2=2 r\;\;\;\;\;\;-D\] |
\[r_2=4 r\;\;\;\;\;\;-B\] |
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Two point charges with distance
\[r\] between them. The electric force between them was calculated to be
\[F_1=9\;N\]. When the distance between them became
\[3r\] and one of the charges was doubled, the new electric force between them becomes
\[F=3 \;\;N\;\;\;\;\;\;-C\] |
\[F=1 \;\;N\;\;\;\;\;\;-A\] |
\[F=4 \;\;N\;\;\;\;\;\;-D\] |
\[F=2 \;\;N\;\;\;\;\;\;-B\] |
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Three charges in a straight line as shown in the figure of the same type
with magnitudes shown in the figure. The direction and magnitude of the force acting
on charge
q2
\[F_{net}=0.0\;\;\;\;\;\;-C\] |
\[F_{net}=\frac{K.q^2}{2r^2}\;\;\;\;\;\;-A\] to the right |
\[F_{net}=\frac{K.q^2}{4r^2}\;\;\;\;\;\;-D\] to the right |
\[F_{net}=\frac{K.q^2}{2r^2}\;\;\;\;\;\;-B\] to the left |
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The force acting on
\[q_1\] was calculated to be 5 Newton
and its direction is shown in the figure
The force acting
from
q3 on q1
equals 3 Newton. Then the second charge's magnitude and type are:
\[q_2= 2.2×10^{-6}\;\;c \;\;\;\;\;\;-C\] positive |
\[q_2= 6.6×10^{-6} \;\;c\;\;\;\;\;\;-A\] negative |
\[q_2= 3.3×10^{-6}\;\;c \;\;\;\;\;\;-D\] negative |
\[q_2= 4.4×10^{-6}\;\;c \;\;\;\;\;\;-B\] positive |
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Two point charges, the first with magnitude \[q_1=- 4\;\;𝜇𝑐\] the second with unknown magnitude and type \[q_2= ?\] The distance between them \[r=0.1\;\; m\] An electron was placed between the charges as shown in the figure at a distance \[r_2= 0.02\;\; m\] from the second charge It was observed that the electron is balanced. The magnitude and type of the second charge equals:
\[q_2= 2.5×10^{-5}\;\;c \;\;\;\;\;\;-C\] negative |
\[q_2= 3.5×10^{-5} \;\;c\;\;\;\;\;\;-A\] negative |
\[q_2= 6.5×10^{-5}\;\;c \;\;\;\;\;\;-D\] positive |
\[q_2= 5.3×10^{-5}\;\;c \;\;\;\;\;\;-B\] positive |
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The figure below shows three point charges in a straight line, all positive. If the total electric force acting on the second charge is zero, then the ratio \[\frac{𝑟_1}{𝑟_2}\] equals:
\[\frac{𝑟_1}{𝑟_2}=0.57\;\;\;\;\;\;-C\] |
\[\frac{𝑟_1}{𝑟_2}=0.81\;\;\;\;\;\;-A\] |
\[\frac{𝑟_1}{𝑟_2}=1.41\;\;\;\;\;\;-D\] |
\[\frac{𝑟_1}{𝑟_2}=1.22\;\;\;\;\;\;-B\] |
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Two charges of different types, the first is positive and four times the second which is negative, were placed with the first charge at the origin and the second at a distance of \[10\;\; Cm\] in the direction of the horizontal axis as shown in the figure. At what position should we place a proton so that the net force on it is zero?
\[X=0.2 \;\;m\;\;\;\;\;\;-C\] |
\[X=0.14 \;\;m\;\;\;\;\;\;-A\] |
\[X=0.16 \;\;m\;\;\;\;\;\;-D\] |
\[X=0.04 \;\;m\;\;\;\;\;\;-B\] |
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Two charged balls with identical charges and equal mass \[m_1=m_2=0.1\;\; Kg\] each were suspended by a non-extensible and massless thread. The balls moved apart due to an electric force such that each thread formed an angle \[𝜃 = 10^0\] with the vertical line. The electric force acting on each ball is:
\[Fe= 0.59\;\; N\;\;\;\;\;\;-C\] |
\[Fe= 0.43\;\; N \;\;\;\;\;\;-A\] |
\[Fe= 0.17\;\; N\;\;\;\;\;\;-D\] |
\[Fe= 0.33\;\; N\;\;\;\;\;\;-B\] |
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In the figure below, four charges are placed at the corners of a square with side length \[r\]. Their magnitudes are shown in the figure. A charge \[q\] is placed at the center of the square. The direction and magnitude of the net electric force acting on the charge \[q\] at the center of the square is:
\[F_{net}=\frac{8 K.q^2}{r^2}\;\;\;\;\;\;-C\] Towards q2 |
\[F_{net}=\frac{12K.q^2}{r^2}\;\;\;\;\;\;-A\] Towards q1 |
\[F_{net}=\frac{12K.q^2}{r^2}\;\;\;\;\;\;-D\] Towards q4 |
\[F_{net}=\frac{8 K.q^2}{r^2}\;\;\;\;\;\;-B\] Towards q2 |
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Two charges of the same type, the first is three times the second charge as shown in the figure below. The distance between them is 0.2 m. If the electric force between them is 0.6 N, then the magnitude of each charge is:
\[q_1= 2.28 × 10^{-6}\;\;c\;\;\;\;\;\;\;\;q_1= 9.42 × 10^{-7}\;\;c\;\;\;\;\;\;-C\] |
\[q_1= 4.5 × 10^{-6}\;\;c\;\;\;\;\;\;\;\;q_1= 4.5 × 10^{-6}\;\;c\;\;\;\;\;\;-A\] |
\[q_1= 1.6 × 10^{-6}\;\;c\;\;\;\;\;\;\;\;q_1= 5.3 × 10^{-7}\;\;c\;\;\;\;\;\;-D\] |
\[q_1= 2.8 × 10^{-6}\;\;c\;\;\;\;\;\;\;\;q_1= 1 × 10^{-7}\;\;c\;\;\;\;\;\;-B\] |
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Three charges with equal magnitudes and types as shown in the figure are placed at the vertices of an equilateral triangle. The direction and magnitude of the force acting on the first charge is equal to:
\[F_{net}=K\frac{2q^2}{r^2}\;\;\;\;\;\;-C\] Towards East |
\[F_{net}=K\frac{q^2}{r^2}\;\;\;\;\;\;-A\] Towards North |
\[F_{net}=K\frac{2q^2}{r^2}\;\;\;\;\;\;-D\] Towards Northeast |
\[F_{net}=K\frac{q^2}{r^2}\;\;\;\;\;\;-B\] Towards East |
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Three charges with equal type and magnitude (each \[2q\]) were placed on the circumference of a semicircle as shown in the figure below with equal distances. A charge \[-q\] was placed at the center of the circle. The magnitude and direction of the force acting on the charge at the center of the circle is:
\[F_{net}=K\frac{2q^2}{r^2}\;\;\;\;\;\;-C\] Towards left |
\[F_{net}=K\frac{q^2}{2r^2}\;\;\;\;\;\;-A\] Towards left |
\[F_{net}=K\frac{2q^2}{4r^2}\;\;\;\;\;\;-D\] Towards northeast |
\[F_{net}=K\frac{q^2}{r^2}\;\;\;\;\;\;-B\] Towards right |
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Assume that the Earth and the Moon were charged with equal charges in magnitude and type, the amount of charge for each is
\[q_e=q_m=q\] and the distance between them is \[r\]
The electric force became equal to the gravitational force between them.
The Moon and Earth were brought to half the distance between them until the electric force and gravitational force became equal again.
The Earth and Moon must be charged with a charge equal to:
\[q_e=q_m=0.25q\;\;\;\;\;\;-C\] |
\[q_e=q_m=0.5q\;\;\;\;\;\;-A\] |
\[q_e=q_m=2q\;\;\;\;\;\;-D\] |
\[q_e=q_m=q\;\;\;\;\;\;-B\] |
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Three equal charges in magnitude and type are placed at the vertices of an equilateral triangle (12 N) as shown in the figure below. The force between two charges was calculated to be 12 N. The resultant force acting on any charge equals:
\[F_{net}=10.39 \;\; N\;\;\;\;\;\;-C\] |
\[F_{net}=24 \;\; N\;\;\;\;\;\;-A\] |
\[F_{net}=20.87 \;\; N\;\;\;\;\;\;-D\] |
\[F_{net}=16.65 \;\; N\;\;\;\;\;\;-B\] |
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Three charges were placed at the vertices of a right-angled triangle as shown in the figure below
The force exerted by the second charge on the first charge was calculated and its components were \[F_{21}=(- 0.4\hat{x} , - 0.3\hat{y} )\]
The force exerted by the third charge on the first charge was calculated and its components were
\[F_{31}=( 0\hat{x} , + 0.6\hat{y} )\] Then one of the following answers matches the previous information and the figure
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Two charges of different types where the first is twice the second \[q_1=+2q ,q_2=-q\] If the electric force exerted by the first charge on the second is \[F_{12}= 10 N \] to the right then the force exerted by the second charge on the first equals
\[F_{21}=10 \;\;N \;\;\;\;\;\;-C\] to the left |
\[F_{21}=20 \;\;N \;\;\;\;\;\;-A\] to the right |
\[F_{21}=10 \;\;N \;\;\;\;\;\;-D\] to the right |
\[F_{21}=20 \;\;N \;\;\;\;\;\;-B\] to the left |
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Two charges with the same magnitude as shown in the figure, the distance
between them is
0.2 m
If the electric force between
them equals
0. 4 N
Then the magnitude of each charge equals
\[q_1=q_2= 1.3 ×10^{-6}\;\;c\;\;\;\;\;\;-C\] |
\[q_1=q_2= 1.7 ×10^{-12} \;\;c\;\;\;\;\;\;-A\] |
\[q_1=q_2= 8.6 ×10^{-12}\;\;c\;\;\;\;\;\;-D\] |
\[q_1=q_2= 3.9 ×10^{-6}\;\;c\;\;\;\;\;\;-B\] |
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Answer the following questions
In the figure below, four charges are placed at the corners of a square with side length \[10\;cm\] Their magnitudes are \[q_1=-3\;µ c\;\;\;\;\;\;\;q_2=-2\;µ c\;\;\;\;\;\;\;q_3=+3\;µ c\;\;\;\;\;\;\;q_4=-2\;µ c\] as shown in the figure below Calculate the electric force acting on \[q_1\]
\[.....................................\;\;\;\;............................................\] \[.....................................\;\;\;\;............................................\] \[.....................................\;\;\;\;............................................\] \[.....................................\;\;\;\;............................................\] \[.....................................\;\;\;\;............................................\]
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