1
WB JEE 2008
+1
-0.25

4 point charges each +q is placed on the circumference of a circle of diameter 2d in such a way that they form a square. The potential at the centre is

A
0
B
$${{4q} \over d}$$
C
$${{4d} \over q}$$
D
$${q \over {4d}}$$
2
WB JEE 2008
+1
-0.25

64 identical spheres of charge q and capacitance C each are combined to form a large sphere. The charge and capacitance of the large sphere is

A
64q, C
B
16q, 4C
C
64q, 4C
D
16q, 64C
3
WB JEE 2023
+1
-0.25  Consider a positively charged infinite cylinder with uniform volume charge density $$\rho > 0$$. An electric dipole consisting of + Q and $$-$$ Q charges attached to opposite ends of a massless rod is oriented as shown in the figure. At the instant as shown in the figure, the dipole will experience,

A
a force to the left and no torque.
B
a force to the right and a clockwise torque.
C
a force to the right and a counter clockwise torque.
D
no force but only a clockwise torque.
4
WB JEE 2023
+1
-0.25  A thin glass rod is bent in a semicircle of radius R. A charge is non-uniformly distributed along the rod with a linear charge density $$\lambda=\lambda_0\sin\theta$$ ($$\lambda_0$$ is a positive constant). The electric field at the centre P of the semicircle is,

A
$$-\frac{\lambda_{o}}{8 \pi \varepsilon_{o} R} \hat{j}$$
B
$$\frac{\lambda_{o}}{8 \pi \varepsilon_{o} R} \hat{j}$$
C
$$\frac{\lambda_{\mathrm{o}}}{8 \pi \varepsilon_{\mathrm{o}} \mathrm{R}} \hat{\mathrm{i}}$$
D
$$-\frac{\lambda_{\mathrm{o}}}{8 \pi \varepsilon_{\mathrm{o}} R} \hat{\mathrm{i}}$$
WB JEE Subjects
Physics
Mechanics
Electricity
Optics
Modern Physics
Chemistry
Physical Chemistry
Inorganic Chemistry
Organic Chemistry
Mathematics
Algebra
Trigonometry
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Calculus
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