Two very long insulated glass rods are charged uniformly by giving them identical charges '\(q\)', each. The rods have lengths \(L\) each and are placed parallel to each other at a distance '\(r\)' apart, where \(r\ll L\). Then, the electric force acting between the rods is proportional to:
 
1. \(\dfrac{1}{r^2}\) 2. \(\dfrac{1}{r}\)
3. \(r\) 4. \(\dfrac{1}{r^3}\)

Subtopic:  Electric Field |
 53%
From NCERT

To unlock all the explanations of this course, you need to be enrolled.

Hints

To unlock all the explanations of this course, you need to be enrolled.


A point charge '\(q\)' is placed at the centre of a spherical cavity at the centre of a conducting sphere. The sphere is initially uncharged. The radius of the cavity is '\(a\)' and that of the sphere is '\(2a\)'. Let the charge on the outer surface of the sphere be \(Q\).
Then,
1. \(q,Q\) are of the same sign and \(|q|=|Q|\)
2. \(q,Q\) are of opposite signs and \(|q|=|Q|\)
3. \(q,Q\) are of the same sign and \(|q|<|Q|\)
4. \(q,Q\) are of opposite signs and \(|q|>|Q|\)
Subtopic:  Gauss's Law |
From NCERT

To unlock all the explanations of this course, you need to be enrolled.

Hints

To unlock all the explanations of this course, you need to be enrolled.


A uniformly charged sphere carrying a charge \(Q\) distributed uniformly on its outer surface is placed in an isotropic medium of dielectric constant '\(K\)'.

The electric field within the medium due to the charge \(Q\) at some point \(P\) is \(\vec E_{Q}\). The Electric field at the same point \(P\) due to induced charge within the medium is \(\vec E_{m}\). Then,
1. \(|\vec E_m|=\left|\dfrac{\vec E_Q}{K}\right|,\) and the two fields are in opposite directions.
2. \(|\vec E_Q|=\left|\dfrac{\vec E_m}{K}\right|,\) and the two fields are in the same direction.
3. \(|\vec E_Q+\vec E_m|=\left|\dfrac{\vec E_Q}{K}\right|,\) and the two fields are in opposite directions.
4. \(|\vec E_Q+\vec E_m|=\left|\dfrac{\vec E_m}{K}\right|,\) and the two fields are in the same direction.
Subtopic:  Electric Field |
From NCERT

To unlock all the explanations of this course, you need to be enrolled.

Hints

To unlock all the explanations of this course, you need to be enrolled.


advertisementadvertisement

Identical point charges (\(q\) each), are placed at the eight corners of a cube of side \(a.\) When one of the charges is removed, the electric field at the center becomes \(E_c.\)
Now, identical point charges (same magnitude \(q\) each), are placed at the four corners of a square of side \(a.\) When one of the charges is removed, the electric field at the center becomes \(E_s.\) Then,
1. \(\dfrac{E_s}{2}=\dfrac{E_C}{3}\) 2. \(\dfrac{E_s}{3}=\dfrac{E_C}{2}\)
3. \(\dfrac{E_s}{\sqrt2}=\dfrac{E_C}{\sqrt3}\) 4. \(\dfrac{E_s}{\sqrt3}=\dfrac{E_C}{\sqrt2}\)
Subtopic:  Electric Field |
 62%
From NCERT

To unlock all the explanations of this course, you need to be enrolled.

Hints

To unlock all the explanations of this course, you need to be enrolled.


Two infinitely large plane parallel sheets carry uniform surface charge densities \(+\sigma,~-\sigma\) and are placed a distance \(d\) apart. The electric fields in the regions , ,  are \(E_1, E_2, E_3\) along the direction \(x\) which is perpendicular to the two planes.
     
Then:
1. \(E_1 < 0, E_2 > 0, E_3 < 0\)
2. \(E_1 < 0, E_2 = 0, E_3 < 0\)
3. \(E_1 = 0, E_2 > 0, E_3 = 0\)
4. \(E_1 < 0, E_2 > 0, E_3 > 0\)
Subtopic:  Electric Field |
 64%
From NCERT

To unlock all the explanations of this course, you need to be enrolled.

Hints

To unlock all the explanations of this course, you need to be enrolled.


A charged particle of charge \(q\) and mass \(m\) is projected vertically upward with a speed \(u\). Acceleration due to gravity \((g)\) acts downwards, while a uniform electric field \(E\) acts along the horizontal. The speed of the projectile's impact on the horizontal is \(v\), while the horizontal range is \(R.\) Then:
1. \(v^2=u^2+2gR\)
2. \(v^2=u^2+2gR\left(\frac{qE}{mg}\right)\)
3. \(v^2=u^2+gR\)
4. \(v^2=u^2+gR\left(\frac{qE}{mg}\right)\)
Subtopic:  Electric Field |
 71%
From NCERT

To unlock all the explanations of this course, you need to be enrolled.

Hints

To unlock all the explanations of this course, you need to be enrolled.


advertisementadvertisement

Which of the following field configurations is/are possible?
Note: \(A,B,C\) are conductors. Other charges may be present in the vicinity.
1. I, III 2. II
3. I, II, III 4. none of I, II, III
Subtopic:  Electric Field |
From NCERT

To unlock all the explanations of this course, you need to be enrolled.

Hints

To unlock all the explanations of this course, you need to be enrolled.


A thin uniform rod of mass \(M\) and length \(L\) is suspended from one of its ends, '\(A\)', so that it can rotate freely about it. A charge '\(q\)' is fixed to its lower end \(B\). A uniform horizontal Electric field is switched on and the rod rotates about \(A\), finally coming to equilibrium – making an angle of \(45^{\circ}\) with the vertical. If the acceleration due to gravity is '\(g\)', then,

1. \(qE =Mg\)
2. \(2qE =Mg\)
3. \(qE =2Mg\)
4. \(\sqrt{2}qE =Mg\)
Subtopic:  Electric Field |
From NCERT

To unlock all the explanations of this course, you need to be enrolled.

Hints

To unlock all the explanations of this course, you need to be enrolled.


Three charges \(q,~q,~-q\)  are placed at the three corners of an equilateral triangle \(ABC\), of side \(a.\)
              
The mid-point of side \(AB\) is \(P\) while the circumcenter of \(ABC\) is \(O\). Let the electric field at \(P\) be \(E_p\) and that at \(O\) be \(E_O.\)
Then, \(E_O:E_P=\)
 
1. \(\dfrac{2}{9}\) 2. \(\dfrac{4}{9}\)
3. \(\dfrac{9}{2}\) 4. \(\dfrac{9}{4}\)
Subtopic:  Electric Field |
From NCERT

To unlock all the explanations of this course, you need to be enrolled.

Hints

To unlock all the explanations of this course, you need to be enrolled.


advertisementadvertisement


A pair of field lines are drawn, connecting the charges \(q_1, q_2\) in addition to the straight field line connecting them. From the above diagram,
1. \(q_1>0, q_2<0~\text{and}~|q_1|>|q_2|\)
2. \(q_1<0, q_2>0~\text{and}~|q_1|>|q_2|\)
3. \(q_1>0, q_2<0~\text{and}~|q_1|<|q_2|\)
4. \(q_1<0, q_2>0~\text{and}~|q_1|<|q_2|\)
Subtopic:  Electric Field |
 62%
From NCERT

To unlock all the explanations of this course, you need to be enrolled.

Hints

To unlock all the explanations of this course, you need to be enrolled.