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All questions of Dynamics of Charged Particles in Static & Uniform Electromagnetic Fields for Physics Exam
A positive charge is placed inside a positively charged spherical shell then- a)Neither attraction nor Repulsion
- b)Repulsion between shell and charge
- c)Cannot conclude
- d)Attraction between shell and charge
Correct answer is option 'A'. Can you explain this answer?
A positive charge is placed inside a positively charged spherical shell then
a)
Neither attraction nor Repulsion
b)
Repulsion between shell and charge
c)
Cannot conclude
d)
Attraction between shell and charge
|
Jayant Mishra answered |
The correct answer is: Neither attraction nor Repulsion
Charge is quantized. It is given by- a)+ ne
- b)– ne
- c)± ne
- d)None of the above
Correct answer is option 'C'. Can you explain this answer?
Charge is quantized. It is given by
a)
+ ne
b)
– ne
c)
± ne
d)
None of the above
|
Nilotpal Basu answered |
The correct answer is: ± ne
Which of the following are quantized?- a)mass and charge
- b)Energy
- c)Mass
- d)All of these
Correct answer is option 'D'. Can you explain this answer?
Which of the following are quantized?
a)
mass and charge
b)
Energy
c)
Mass
d)
All of these
|
Mikhi Mouse answered |
Yes the mass and charge are quantized because the charge is produced by the transfer of electrons and the electrons are transferable only as a whole number .also the mass depends on the number of electrons and so it is also quantized.i think so .anybody who felt it's wrong you can say your comments.
A long string with a charge of λ per unit length passes through an imaginary cube of edge l. The maximum possible flux of electric field through the cube will be- a)
- b)
- c)
- d)
Correct answer is option 'A'. Can you explain this answer?
A long string with a charge of λ per unit length passes through an imaginary cube of edge l. The maximum possible flux of electric field through the cube will be
a)
b)
c)
d)
|
Pie Academy answered |
Maximum length of string = 
Maximum enclosed charge =
Maximum enclosed charge =
The correct answer is: 
When a charged body is brought near an uncharged conductor on the insulating stand- a)The nearer end of the conductor acquires the same charge while the farther end opposite charge
- b)No charge is induced on the conductor
- c)The nearer end of the conductor acquires opposite charge and the farther end the same charge
- d)None of the above is correct
Correct answer is option 'C'. Can you explain this answer?
When a charged body is brought near an uncharged conductor on the insulating stand
a)
The nearer end of the conductor acquires the same charge while the farther end opposite charge
b)
No charge is induced on the conductor
c)
The nearer end of the conductor acquires opposite charge and the farther end the same charge
d)
None of the above is correct
|
|
Jayant Mishra answered |
The correct answer is: The nearer end of the conductor acquires opposite charge and the farther end the same charge
A charge +q is placed (a, 0, 0) and another +q is placed (-a, 0, 0). A charge –q is placed at the origin. If it is slightly displaced along y-axis. Then - a)It will move away
- b)It will execute SHM
- c)It will stand at the displaced position
- d)It will oscillate but not SHM
Correct answer is option 'B'. Can you explain this answer?
A charge +q is placed (a, 0, 0) and another +q is placed (-a, 0, 0). A charge –q is placed at the origin. If it is slightly displaced along y-axis. Then
a)
It will move away
b)
It will execute SHM
c)
It will stand at the displaced position
d)
It will oscillate but not SHM
|
Vedika Singh answered |
The correct answer is: It will execute SHMTwo spheres P and Q are supported on two insulated stands and placed next to each other. Sphere P has a charge of +10C and sphere Q is neutral which of the following statement is correct?- a)After some time, the charges on P are transferred to Q
- b)After some time, Q becomes negatively charge
- c)After some time, Q is still neutral
- d)P and Q together have net charge of +5C.
Correct answer is option 'C'. Can you explain this answer?
Two spheres P and Q are supported on two insulated stands and placed next to each other. Sphere P has a charge of +10C and sphere Q is neutral which of the following statement is correct?
a)
After some time, the charges on P are transferred to Q
b)
After some time, Q becomes negatively charge
c)
After some time, Q is still neutral
d)
P and Q together have net charge of +5C.
|
|
Jayant Mishra answered |
The correct answer is: After some time, Q is still neutral
A spherical charged conductor has surface density σ of charge. The electric field on its surface is E. If the radius of the sphere is doubled keeping the surface density of charged unchanged then the electric field on the surface of the new sphere will be- a)4E
- b)E/4
- c)E
- d)E/2
Correct answer is option 'B'. Can you explain this answer?
A spherical charged conductor has surface density σ of charge. The electric field on its surface is E. If the radius of the sphere is doubled keeping the surface density of charged unchanged then the electric field on the surface of the new sphere will be
a)
4E
b)
E/4
c)
E
d)
E/2
|
|
Jayant Mishra answered |
The correct answer is: E/4
If the flux of the electric field through a closed surface is zero- a)the net charge in the vicinity of the surface must be zero
- b)the net charge inside the surface must be zero
- c)the electric field must be non-zero everywhere on the surface
- d)the electric field must be zero everywhere on the surface
Correct answer is option 'B'. Can you explain this answer?
If the flux of the electric field through a closed surface is zero
a)
the net charge in the vicinity of the surface must be zero
b)
the net charge inside the surface must be zero
c)
the electric field must be non-zero everywhere on the surface
d)
the electric field must be zero everywhere on the surface
|
|
Vedika Singh answered |
Flux across a closed surface, 
Since,
so, charge enclosed q = 0
Since,
so, charge enclosed q = 0The correct answer is: the net charge inside the surface must be zero
Which of the following should not be done during lightning.
1. Stay in a building with a lightning conductor installed on the roof.
2. Stand near a window with a metal frame.
3. Crouch down in an open field.- a)(2) and (3) only
- b)(1) and (2) only
- c)(2) only
- d)(1) only
Correct answer is option 'D'. Can you explain this answer?
Which of the following should not be done during lightning.
1. Stay in a building with a lightning conductor installed on the roof.
2. Stand near a window with a metal frame.
3. Crouch down in an open field.
1. Stay in a building with a lightning conductor installed on the roof.
2. Stand near a window with a metal frame.
3. Crouch down in an open field.
a)
(2) and (3) only
b)
(1) and (2) only
c)
(2) only
d)
(1) only
|
Eesha Patel answered |
Understanding Lightning Safety
Lightning is a natural phenomenon that can be extremely dangerous. Knowing what to do and what not to do during a lightning storm is crucial for safety.
1. Buildings with Lightning Conductors
- Staying indoors is one of the safest actions during a lightning storm.
- Buildings with lightning conductors are designed to safely redirect lightning strikes into the ground, minimizing risk.
2. Standing Near Metal Frames
- Unsafe Action: Standing near a window with a metal frame can be dangerous.
- Metal can conduct electricity, and if lightning strikes the building, the metal frame may conduct the electrical charge, posing a risk to anyone nearby.
3. Crouching in an Open Field
- Unsafe Action: Crouching down in an open field is not advisable.
- In an open area, you are the tallest object, increasing the likelihood of a lightning strike. Instead, seek shelter immediately.
Conclusion
The correct answer is option 'D' because standing near a window with a metal frame is particularly hazardous during lightning storms. It exposes you to the risk of electrical conduction, while crouching in an open field also poses significant danger.
In summary, prioritize safety by avoiding metal structures and open fields during thunderstorms, while seeking shelter in a well-constructed building.
Lightning is a natural phenomenon that can be extremely dangerous. Knowing what to do and what not to do during a lightning storm is crucial for safety.
1. Buildings with Lightning Conductors
- Staying indoors is one of the safest actions during a lightning storm.
- Buildings with lightning conductors are designed to safely redirect lightning strikes into the ground, minimizing risk.
2. Standing Near Metal Frames
- Unsafe Action: Standing near a window with a metal frame can be dangerous.
- Metal can conduct electricity, and if lightning strikes the building, the metal frame may conduct the electrical charge, posing a risk to anyone nearby.
3. Crouching in an Open Field
- Unsafe Action: Crouching down in an open field is not advisable.
- In an open area, you are the tallest object, increasing the likelihood of a lightning strike. Instead, seek shelter immediately.
Conclusion
The correct answer is option 'D' because standing near a window with a metal frame is particularly hazardous during lightning storms. It exposes you to the risk of electrical conduction, while crouching in an open field also poses significant danger.
In summary, prioritize safety by avoiding metal structures and open fields during thunderstorms, while seeking shelter in a well-constructed building.
A charged ball B hangs from a silk thread S, which make an angle θ and a large conducting sheet P as shown in the figure. The surface charge density σ of the sheet is proportional to 
- a)sin θ
- b)cot θ
- c)cos θ
- d)tan θ
Correct answer is option 'D'. Can you explain this answer?
A charged ball B hangs from a silk thread S, which make an angle θ and a large conducting sheet P as shown in the figure. The surface charge density σ of the sheet is proportional to
a)
sin θ
b)
cot θ
c)
cos θ
d)
tan θ
|
|
Vedika Singh answered |
For equilibrium
Dividing, we get
The correct answer is: tan θ
Given 
The electric flux through 1m2 area in YZ plane is- a)10Vm
- b)49Vm
- c)7Vm
- d)100Vm
Correct answer is option 'C'. Can you explain this answer?
Given The electric flux through 1m2 area in YZ plane is
The electric flux through 1m2 area in YZ plane isa)
10Vm
b)
49Vm
c)
7Vm
d)
100Vm
|
|
Vedika Singh answered |
For yz plane,
So, flux across yz plane is given by
The correct answer is: 7Vm
So, flux across yz plane is given by
The correct answer is: 7Vm
A uniform electric field of 100 V/m is directed at 30° with the positive x-axis as shown in figure. Find the potential difference VBA. If OA = 2m and OB = 4m. O is the origin.
- a)
- b)
- c)
- d)
Correct answer is option 'C'. Can you explain this answer?
A uniform electric field of 100 V/m is directed at 30° with the positive x-axis as shown in figure. Find the potential difference VBA. If OA = 2m and OB = 4m. O is the origin.
a)
b)
c)
d)
|
|
Jayant Mishra answered |
Electric field in vector form can be written
A = (–2m, 0, 0)
B = (0.4m, 0)
VAB = VB – VA
Electric charge is uniformly distributed along a long straight wire of radius 1mm. The charge per cm length of the wire is Q coulomb. Another cylindrical surface of radius 50cm and length 1m symmetrically encloses the wire as shown in figure. The total electric flux passing through the cylinder surface is
- a)
- b)
- c)
- d)
Correct answer is option 'A'. Can you explain this answer?
Electric charge is uniformly distributed along a long straight wire of radius 1mm. The charge per cm length of the wire is Q coulomb. Another cylindrical surface of radius 50cm and length 1m symmetrically encloses the wire as shown in figure. The total electric flux passing through the cylinder surface is
a)
b)
c)
d)
|
|
Jayant Mishra answered |
The diagram shows five charged metal spheres suspended by string. The charge of each sphere is +5C, –2C, +3C, –4C and +2C as shown. If the five spheres simultaneously contact together. Find the net charge on them.
- a)–16C
- b)+16C
- c)+4C
- d)–4C
Correct answer is option 'C'. Can you explain this answer?
The diagram shows five charged metal spheres suspended by string. The charge of each sphere is +5C, –2C, +3C, –4C and +2C as shown. If the five spheres simultaneously contact together. Find the net charge on them.
a)
–16C
b)
+16C
c)
+4C
d)
–4C
|
|
Vedika Singh answered |
For finding the net charge we will add all the charges on all spheres.
= +5C + (-2C) + (+3C) + (-4C) + (2C)
The correct answer is: +4C
A sphere of radius R has a uniform of volume charge density. The electric potential at a point r, r < R is
- a)due to the charge in the spherical shell of inner and outer radii r and R only
- b)Independent of r
- c)due to the charge inside a sphere of radius r only
- d)due to entire charge of the sphere
Correct answer is option 'C'. Can you explain this answer?
A sphere of radius R has a uniform of volume charge density. The electric potential at a point r, r < R is
a)
due to the charge in the spherical shell of inner and outer radii r and R only
b)
Independent of r
c)
due to the charge inside a sphere of radius r only
d)
due to entire charge of the sphere
|
|
Jayant Mishra answered |
The correct answer is: due to entire charge of the sphere
A charge q1 exert some force on a second charge q2. If a third charge q3 is brought near q1 the force exerted by q1 on q2- a)Decrease
- b)Remain the same
- c)Increase
- d)Increase If q3 is of same sign as q and decrease. If q3 is of opposite sign as q1.
Correct answer is option 'B'. Can you explain this answer?
A charge q1 exert some force on a second charge q2. If a third charge q3 is brought near q1 the force exerted by q1 on q2
a)
Decrease
b)
Remain the same
c)
Increase
d)
Increase If q3 is of same sign as q and decrease. If q3 is of opposite sign as q1.
|
|
Jayant Mishra answered |
The correct answer is: Remain the same
A spherical condenser has inner and outer sphere of radii a and b respectively. The space between the two is filled with air. The difference between the capacities of two condensers formed when outer sphere is earthed and when inner sphere is earthed will be- a)0
- b)
- c)
- d)
Correct answer is option 'D'. Can you explain this answer?
A spherical condenser has inner and outer sphere of radii a and b respectively. The space between the two is filled with air. The difference between the capacities of two condensers formed when outer sphere is earthed and when inner sphere is earthed will be
a)
0
b)
c)
d)
|
|
Pie Academy answered |
Capacity of spherical condenser when outer sphere is earthed 
Capacity of spherical condenser when inner sphere is earthed
Difference in their capacity 
The correct answer is:
Capacity of spherical condenser when inner sphere is earthed
Difference in their capacity The correct answer is:
Two equal negative charge (–q each) are fixed at point (0, a) and (0, –a) on the y-axis. A positive charge Q is released from rest at the points (29, 0) on the x-axis is the charge Q will- a)move to origin and remain at rest
- b)move to infinity
- c)execute oscillation but not simple harmonic motion
- d)execute simple harmonic motion about the origin
Correct answer is option 'C'. Can you explain this answer?
Two equal negative charge (–q each) are fixed at point (0, a) and (0, –a) on the y-axis. A positive charge Q is released from rest at the points (29, 0) on the x-axis is the charge Q will
a)
move to origin and remain at rest
b)
move to infinity
c)
execute oscillation but not simple harmonic motion
d)
execute simple harmonic motion about the origin
|
|
Vedika Singh answered |
The SI unit of electric flux is- a)volt × metre
- b)Joule/coulomb
- c)Newton/coulomb
- d)Weber
Correct answer is option 'A'. Can you explain this answer?
The SI unit of electric flux is
a)
volt × metre
b)
Joule/coulomb
c)
Newton/coulomb
d)
Weber
|
|
Jayant Mishra answered |
Electric flux = E.A
The correct answer is: volt × metre
The correct answer is: volt × metre
Effective mass of an electron in an semiconductor- a)can never be negative
- b)can be positive or negative
- c)Depend on its spin
- d)can never be positive
Correct answer is option 'A'. Can you explain this answer?
Effective mass of an electron in an semiconductor
a)
can never be negative
b)
can be positive or negative
c)
Depend on its spin
d)
can never be positive
|
|
Jayant Mishra answered |
The correct answer is: can never be negative
Two identical point charge are placed at a separation of r. P is a point on the line joining the charges, at a distance x from any one charge. The field at P is E. E is plotted against x, for value of x from close to zero to slightly less than r. Which of the following best represent the resulting curve.
- a)
- b)
- c)
- d)
Correct answer is option 'D'. Can you explain this answer?
Two identical point charge are placed at a separation of r. P is a point on the line joining the charges, at a distance x from any one charge. The field at P is E. E is plotted against x, for value of x from close to zero to slightly less than r. Which of the following best represent the resulting curve.
a)
b)
c)
d)
|
|
Vedika Singh answered |
Option D : shows a curve that increases sharply as x approaches zero and then drops to zero at distance r. This reflects the 
relationship and is the correct depiction of the electric field around a point charge.
relationship and is the correct depiction of the electric field around a point charge.A charged of Q coulomb is placed on a solid piece of metal of irregular shape the charge will distribute itself.- a)Such that the potential energy of the system is minimised
- b)Uniformly in the metal object
- c)Such that total heat loss is minimised
- d)Uniformly on the surface of the object
Correct answer is option 'A'. Can you explain this answer?
A charged of Q coulomb is placed on a solid piece of metal of irregular shape the charge will distribute itself.
a)
Such that the potential energy of the system is minimised
b)
Uniformly in the metal object
c)
Such that total heat loss is minimised
d)
Uniformly on the surface of the object
|
Shilpa Datta answered |
The correct answer is: Such that the potential energy of the system is minimised
A negative charged rod is held near a conductor X that is earthed shown in the figure. Here X is
- a)Uncharged and at positive potential
- b)Positively charged and at earth potential
- c)Negatively charged and at earth potential
- d)Uncharged and at negative potential
Correct answer is option 'B'. Can you explain this answer?
A negative charged rod is held near a conductor X that is earthed shown in the figure. Here X is
a)
Uncharged and at positive potential
b)
Positively charged and at earth potential
c)
Negatively charged and at earth potential
d)
Uncharged and at negative potential
|
|
Mister Genius answered |
The correct answer is: Positively charged and at earth potential
Let 
denote the permittivity of vacuum, the dimensional formula of the ε0 is let M = Mass, L = length, T = time and I = electric current. Then
- a)
- b)
- c)
- d)
Correct answer is option 'D'. Can you explain this answer?
Let denote the permittivity of vacuum, the dimensional formula of the ε0 is let M = Mass, L = length, T = time and I = electric current. Then
denote the permittivity of vacuum, the dimensional formula of the ε0 is let M = Mass, L = length, T = time and I = electric current. Thena)
b)
c)
d)
|
|
Pie Academy answered |
Using Coulomb law, F = 1/4πϵ0(q1q2/R2)
⇒ϵ0 = q1q2/4πFR2
Substituting the units in the equation:
So, ϵ0 = C2/N.m2
=[AT]2/MLT-2.L2
[∈0]=[M-1L-3T4A2]
A metallic sphere of radius r and carrying a charge q is enclosed by a dielectric shell of thickness δ outer radius r2 and relative permittivity ε The medium elsewhere is air. The potential V(r) for r > r2 is- a)
- b)
- c)
- d)
Correct answer is option 'B'. Can you explain this answer?
A metallic sphere of radius r and carrying a charge q is enclosed by a dielectric shell of thickness δ outer radius r2 and relative permittivity ε The medium elsewhere is air. The potential V(r) for r > r2 is
a)
b)
c)
d)
|
|
Vedika Singh answered |
E = P = D = 0 [Inside the metal sphere]
An electric dipole is place in a uniform electric field. The net electric field on the dipole- a)can never be zero
- b)depend on the orientation of dipole
- c)depend on the strength of the dipole
- d)is always zero
Correct answer is option 'D'. Can you explain this answer?
An electric dipole is place in a uniform electric field. The net electric field on the dipole
a)
can never be zero
b)
depend on the orientation of dipole
c)
depend on the strength of the dipole
d)
is always zero
|
Oorvi Agrawal answered |
Explanation:
An electric dipole consists of two equal and opposite charges separated by a small distance. When an electric dipole is placed in a uniform electric field, it experiences a torque due to the interaction of the charges with the field. This torque tends to align the dipole with the electric field.
Net Electric Force on the Dipole:
The net electric force on the dipole is the vector sum of the forces experienced by the positive and negative charges that make up the dipole.
Force on Positive Charge:
The positive charge experiences a force in the direction of the electric field. This force is given by the equation F = qE, where F is the force, q is the charge, and E is the electric field.
Force on Negative Charge:
The negative charge experiences a force in the opposite direction of the electric field. This force is also given by the equation F = qE, where F is the force, q is the charge, and E is the electric field.
Net Force:
Since the electric field is uniform, the magnitude of the forces on the positive and negative charges are equal. However, the forces act in opposite directions. Therefore, the net force on the dipole is zero.
Explanation of Options:
a) The net electric force on the dipole can never be zero - This is incorrect, as explained above, the net force on the dipole is zero when it is placed in a uniform electric field.
b) The net electric force on the dipole depends on the orientation of the dipole - This is incorrect, as the net force on the dipole is always zero regardless of its orientation.
c) The net electric force on the dipole depends on the strength of the dipole - This is incorrect, as the net force on the dipole is determined by the electric field and the charges, not the strength of the dipole.
d) The net electric force on the dipole is always zero - This is the correct answer, as explained above, the net force on the dipole is always zero when it is placed in a uniform electric field.
Therefore, option D is the correct answer.
An electric dipole consists of two equal and opposite charges separated by a small distance. When an electric dipole is placed in a uniform electric field, it experiences a torque due to the interaction of the charges with the field. This torque tends to align the dipole with the electric field.
Net Electric Force on the Dipole:
The net electric force on the dipole is the vector sum of the forces experienced by the positive and negative charges that make up the dipole.
Force on Positive Charge:
The positive charge experiences a force in the direction of the electric field. This force is given by the equation F = qE, where F is the force, q is the charge, and E is the electric field.
Force on Negative Charge:
The negative charge experiences a force in the opposite direction of the electric field. This force is also given by the equation F = qE, where F is the force, q is the charge, and E is the electric field.
Net Force:
Since the electric field is uniform, the magnitude of the forces on the positive and negative charges are equal. However, the forces act in opposite directions. Therefore, the net force on the dipole is zero.
Explanation of Options:
a) The net electric force on the dipole can never be zero - This is incorrect, as explained above, the net force on the dipole is zero when it is placed in a uniform electric field.
b) The net electric force on the dipole depends on the orientation of the dipole - This is incorrect, as the net force on the dipole is always zero regardless of its orientation.
c) The net electric force on the dipole depends on the strength of the dipole - This is incorrect, as the net force on the dipole is determined by the electric field and the charges, not the strength of the dipole.
d) The net electric force on the dipole is always zero - This is the correct answer, as explained above, the net force on the dipole is always zero when it is placed in a uniform electric field.
Therefore, option D is the correct answer.
A charge Q is enclosed by a Gaussian spherical surface of radius R. If the radius is doubled, then the outward electric flux will- a)remain the same
- b)be doubled
- c)increase four times
- d)be reduced to half
Correct answer is option 'A'. Can you explain this answer?
A charge Q is enclosed by a Gaussian spherical surface of radius R. If the radius is doubled, then the outward electric flux will
a)
remain the same
b)
be doubled
c)
increase four times
d)
be reduced to half
|
|
Vedika Singh answered |
Since, flux across a closed surface depends only on the charge enclosed. So, it will remain same
The correct answer is: remain the same
Twenty seven drops of water of the same size are equally and similarly charged. They are then united to from a bigger drop. By what factor will the electrical potential changes.- a)3 times
- b)9 times
- c)6 times
- d)27 times
Correct answer is option 'B'. Can you explain this answer?
Twenty seven drops of water of the same size are equally and similarly charged. They are then united to from a bigger drop. By what factor will the electrical potential changes.
a)
3 times
b)
9 times
c)
6 times
d)
27 times
|
|
Vedika Singh answered |
The correct answer is: 9 times
Which of the following is a possible value of charge?- a)10.8 × 10–19 C
- b)13.8 × 10–19 C
- c)12.8 × 10–19 C
- d)All of the above
Correct answer is option 'C'. Can you explain this answer?
Which of the following is a possible value of charge?
a)
10.8 × 10–19 C
b)
13.8 × 10–19 C
c)
12.8 × 10–19 C
d)
All of the above
|
|
Athul Chaudhary answered |
The correct answer is: 12.8 × 10–19 C
A charge q is divided into two parts q1 and (q – q1). What is the ratio 
so that the force between two parts placed at a given distance apart is maximum.- a)1 : 4
- b)1 : 1
- c)2 : 1
- d)1 : 2
Correct answer is option 'C'. Can you explain this answer?
A charge q is divided into two parts q1 and (q – q1). What is the ratio so that the force between two parts placed at a given distance apart is maximum.
so that the force between two parts placed at a given distance apart is maximum.a)
1 : 4
b)
1 : 1
c)
2 : 1
d)
1 : 2
|
|
Jayant Mishra answered |
F = k(q1)(q – q1)
F will be maximum. If q1(q – q1) is maximum
∴ q1 = (q – q1)
⇒ q = 2q1
⇒ q/q1 = 2:1
The correct answer is: 2 : 1
F will be maximum. If q1(q – q1) is maximum
∴ q1 = (q – q1)
⇒ q = 2q1
⇒ q/q1 = 2:1
The correct answer is: 2 : 1
Electric field in the region is given by 
Here, α is a constant of proper dimensions. The total flux passing through a cube bounded by the surfaces x = l , x = 2l, y = 0, y = l, z = 0, z = l.- a)αl3
- b)3αl3
- c)2αl3
- d)αl2
Correct answer is option 'A'. Can you explain this answer?
Electric field in the region is given by Here, α is a constant of proper dimensions. The total flux passing through a cube bounded by the surfaces x = l , x = 2l, y = 0, y = l, z = 0, z = l.
Here, α is a constant of proper dimensions. The total flux passing through a cube bounded by the surfaces x = l , x = 2l, y = 0, y = l, z = 0, z = l.a)
αl3
b)
3αl3
c)
2αl3
d)
αl2
|
|
Jayant Mishra answered |
Except the faces ABCD and EFGH, 
for all the faces as 
for all the faces as So, flux through the cube
The correct answer is: αl3
Which of the following statement concerning lightning is/are correct?
1. It is a result of charging
2. The charge at the bottom of the clouds and those induced on the top of the roofs of buildings form a very strong electric field.
3. Lightning cause the thunder we hear- a)(2) and (3) only
- b)(1) and (2) only
- c)(1), (2) and (3)
- d)(1) only
Correct answer is option 'D'. Can you explain this answer?
Which of the following statement concerning lightning is/are correct?
1. It is a result of charging
2. The charge at the bottom of the clouds and those induced on the top of the roofs of buildings form a very strong electric field.
3. Lightning cause the thunder we hear
1. It is a result of charging
2. The charge at the bottom of the clouds and those induced on the top of the roofs of buildings form a very strong electric field.
3. Lightning cause the thunder we hear
a)
(2) and (3) only
b)
(1) and (2) only
c)
(1), (2) and (3)
d)
(1) only
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Pie Academy answered |
a) Lightning is a naturally occurring electrostatic discharge during which two electrically charged regions in the atmosphere or ground temporarily equalize themselves, causing the instantaneous release of as much as one gigajoule of energy.
b) The charge at the bottom of the clouds and those induced on the top of the roofs of buildings form a very strong electric field.
c) Lightning causes thunder, a sound from the shock wave which develops as gases in the vicinity of the discharge experience a sudden increase in pressure.
In some charging process, a body acquires net positive charge then the mass of body.- a)Remain same
- b)Decrease
- c)Increases
- d)None of the above
Correct answer is option 'B'. Can you explain this answer?
In some charging process, a body acquires net positive charge then the mass of body.
a)
Remain same
b)
Decrease
c)
Increases
d)
None of the above
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Vedika Singh answered |
Since we know that charging of a body depends upon transfer of electrons. So, if a body becomes negatively charged it will gain electrons that is its mass will increase and if a body becomes positively charged it loses electrons hence its mass will decrease.
A diagram of an irregularly shaped charged conductor is shown at the right figure. Four location along the surface are labeled A, B, C, D. Rank these locations in increasing order of the strength of their electric field beginning with the smallest electric field.
- a)C < D < A < B
- b)D < A < C < B
- c)A < D < B < C
- d)B < C < D < A
Correct answer is option 'D'. Can you explain this answer?
A diagram of an irregularly shaped charged conductor is shown at the right figure. Four location along the surface are labeled A, B, C, D. Rank these locations in increasing order of the strength of their electric field beginning with the smallest electric field.
a)
C < D < A < B
b)
D < A < C < B
c)
A < D < B < C
d)
B < C < D < A
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Jayant Mishra answered |
For conducting surface, electric field are strongest at the location where the curvature is the greatest. A projection (such as at point A) is the extreme case of high carvature. A flat section of a surface (such as point B) is on the opposite extreme with the no curvature. So, point B is listed first and point A is listed last. Since point D is on a section of the surface which curve more than point C. The field at point C is more than field at point B.
The correct answer is: B < C < D < A
Electric potential at any point x, y, z in the space is given V=4x2−3x- a)(8x - 3)i
- b)-(8x - 3)i
- c)-8xi
- d)8xi
Correct answer is option 'B'. Can you explain this answer?
Electric potential at any point x, y, z in the space is given V=4x2−3x
a)
(8x - 3)i
b)
-(8x - 3)i
c)
-8xi
d)
8xi
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Pie Academy answered |
V = 4x2 - 3x
Ex = ∂V/∂x = 8x - 3
Ey = ∂V/∂y = 0
Ez = ∂V/∂z = 0
So, E = -(8x - 3)
Ex = ∂V/∂x = 8x - 3
Ey = ∂V/∂y = 0
Ez = ∂V/∂z = 0
So, E = -(8x - 3)
Two concentric sphere of radii R and r have similar charges with equal surface charge density σ. The electric potential at their common centre is- a)
- b)
- c)
- d)
Correct answer is option 'D'. Can you explain this answer?
Two concentric sphere of radii R and r have similar charges with equal surface charge density σ. The electric potential at their common centre is
a)
b)
c)
d)
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Pie Academy answered |
By superposition Principle.
Electric Potential at common centre is
Electric Potential at common centre is
The SI unit of electric flux is - a)N C-1 m-2
- b)N C m-2
- c)N C-1 m2
- d)N C-2 m2
Correct answer is option 'C'. Can you explain this answer?
The SI unit of electric flux is
a)
N C-1 m-2
b)
N C m-2
c)
N C-1 m2
d)
N C-2 m2
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Vedika Singh answered |
Electric flux has SI units of volt metres (V m), or, equivalently, newton metres squared per coulomb (N m2 C−1). Thus, the SI base units of electric flux are kg·m3·s−3·A−1
Charge on the outer sphere is q and the inner sphere is grounded. Then the charge q' on the inner sphere r2 > r1.
- a)
- b)
- c)
- d)0
Correct answer is option 'C'. Can you explain this answer?
Charge on the outer sphere is q and the inner sphere is grounded. Then the charge q' on the inner sphere r2 > r1.
a)
b)
c)
d)
0
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Pie Academy answered |
Potential at the surface of inner sphere = 0 (grounded)
A point charge is kept at the mid point between two large parallel grounded conducting plates. Assuming no gravity. The charge is displaced a little towards the right plate. The charge will now- a)Move towards the left plate
- b)Move towards the right plate
- c)Stay where it is
- d)Oscillate between the plates
Correct answer is option 'B'. Can you explain this answer?
A point charge is kept at the mid point between two large parallel grounded conducting plates. Assuming no gravity. The charge is displaced a little towards the right plate. The charge will now
a)
Move towards the left plate
b)
Move towards the right plate
c)
Stay where it is
d)
Oscillate between the plates
|
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Jayant Mishra answered |
When the charge is placed at the mid point, opposite charge will induced on both the plates equally. But when q is displaced toward the right, more charge of the opposite sign will get induced on the right plate than on the left plate. Hence the point charge will feel a net attraction towards the right plate.
The correct answer is: Move towards the right plate
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