1
JEE Main 2020 (Online) 9th January Morning Slot
+4
-1
Consider a sphere of radius R which carries a uniform charge density $$\rho$$. If a sphere of radius $${{R \over 2}}$$ is carved out of it, as shown, the ratio $${{\left| {\overrightarrow {{E_A}} } \right|} \over {\left| {\overrightarrow {{E_B}} } \right|}}$$ of magnitude of electric field $${\overrightarrow {{E_A}} }$$ and $${\overrightarrow {{E_B}} }$$, respectively, at points A and B due to the remaining portion is :
A
$${{17} \over {54}}$$
B
$${{18} \over {54}}$$
C
$${{18} \over {34}}$$
D
$${{21} \over {34}}$$
2
JEE Main 2020 (Online) 9th January Morning Slot
+4
-1
An electric dipole of moment
$$\overrightarrow p = \left( { - \widehat i - 3\widehat j + 2\widehat k} \right) \times {10^{ - 29}}$$ C.m is
at the origin (0, 0, 0). The electric field due to this dipole at
$$\overrightarrow r = + \widehat i + 3\widehat j + 5\widehat k$$ (note that $$\overrightarrow r .\overrightarrow p = 0$$ ) is parallel to :
A
$$\left( { + \widehat i + 3\widehat j - 2\widehat k} \right)$$
B
$$\left( { + \widehat i - 3\widehat j - 2\widehat k} \right)$$
C
$$\left( { - \widehat i + 3\widehat j - 2\widehat k} \right)$$
D
$$\left( { - \widehat i - 3\widehat j + 2\widehat k} \right)$$
3
JEE Main 2020 (Online) 8th January Evening Slot
+4
-1
A particle of mass m and charge q is released from rest in a uniform electric field. If there is no other force on the particle, the dependence of its speed v on the distance x travelled by it is correctly given by (graphs are schematic and not drawn to scale)
A
B
C
D
4
JEE Main 2020 (Online) 8th January Evening Slot
+4
-1
Consider two charged metallic spheres S1 and S2 of radii R1 and R2, respectively. The electric fields E1 (on S1) and E2 (on S2) on their surfaces are such that E1/E2 = R1/R2. Then the ratio V1 (on S1) / V2 (on S2) of the electrostatic potentials on each sphere is :
A
(R1/R2)2
B
(R2/R1)
C
(R1/R2)3
D
R1/R2
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