1
WB JEE 2018
MCQ (Single Correct Answer)
+1
-0.25
Change Language
Consider a region in free space bounded by the surfaces of an imaginary cube having sides of length a as shown in the figure. A charge + Q is placed at the centre O of the cube. P is such a point outside the cube that the line OP perpendicularly intersects the surface ABCD at R and also OR = RP = a/2. A charge + Q is placed at point P also. What is the total electric flux through the five faces of the cube other than ABCD?

WB JEE 2018 Physics - Electrostatics Question 18 English
A
$${Q \over {{\varepsilon _0}}}$$
B
$${5Q \over {{6\varepsilon _0}}}$$
C
$${10Q \over {{6\varepsilon _0}}}$$
D
zero
2
WB JEE 2018
MCQ (Single Correct Answer)
+1
-0.25
Change Language
Four equal charges of value + Q are placed at any four vertices of a regular hexagon of side 'a'. By suitably choosing the vertices, what can be maximum possible magnitude of electric field at the centre of the hexagon?
A
$${Q \over {4\pi {\varepsilon _0}{a^2}}}$$
B
$${{\sqrt 2 Q} \over {4\pi {\varepsilon _0}{a^2}}}$$
C
$${{\sqrt 3 Q} \over {4\pi {\varepsilon _0}{a^2}}}$$
D
$${{2Q} \over {4\pi {\varepsilon _0}{a^2}}}$$
3
WB JEE 2018
MCQ (Single Correct Answer)
+1
-0.25
Change Language
A proton of mass m moving with a speed v (< < c, velocity of light in vacuum) completes a circular orbit in time T in a uniform magnetic field. If the speed of the proton is increased to $$\sqrt 2 $$ v, what will be time needed to complete the circular orbit?
A
$$\sqrt 2 $$T
B
T
C
$${{T \over {\sqrt 2 }}}$$
D
$${{T \over 2}}$$
4
WB JEE 2018
MCQ (Single Correct Answer)
+1
-0.25
Change Language
A uniform current is flowing along the length of an infinite, straight, thin, hollow cylinder of radius R. The magnetic field B produced at a perpendicular distance d from the axis of the cylinder is plotted in a graph. Which of the following figures looks like the plot?
A
WB JEE 2018 Physics - Magnetism Question 18 English Option 1
B
WB JEE 2018 Physics - Magnetism Question 18 English Option 2
C
WB JEE 2018 Physics - Magnetism Question 18 English Option 3
D
WB JEE 2018 Physics - Magnetism Question 18 English Option 4
EXAM MAP
Medical
NEET
Graduate Aptitude Test in Engineering
GATE CSEGATE ECEGATE EEGATE MEGATE CEGATE PIGATE IN
CBSE
Class 12