JEE Main 2021 (Online) 24th February Morning Shift | Electrostatics Question 188 | Physics

JEE Main 2021 (Online) 24th February Morning Shift

MCQ (Single Correct Answer)

-1

A cube of side 'a' has point charges +Q located at each of its vertices except at the origin where the charge is $$-$$Q. The electric field at the centre of cube is :

JEE Main 2021 (Online) 24th February Morning Shift Physics - Electrostatics Question 188 English

JEE Main 2021 (Online) 24th February Morning Shift Physics - Electrostatics Question 188 English

$${{2Q} \over {3\sqrt 3 \pi {\varepsilon _0}{a^2}}}\left( {\widehat x + \widehat y + \widehat z} \right)$$

$${{ - Q} \over {3\sqrt 3 \pi {\varepsilon _0}{a^2}}}\left( {\widehat x + \widehat y + \widehat z} \right)$$

$${Q \over {3\sqrt 3 \pi {\varepsilon _0}{a^2}}}\left( {\widehat x + \widehat y + \widehat z} \right)$$

$${{ - 2Q} \over {3\sqrt 3 \pi {\varepsilon _0}{a^2}}}\left( {\widehat x + \widehat y + \widehat z} \right)$$

JEE Main 2020 (Online) 6th September Evening Slot

MCQ (Single Correct Answer)

-1

Consider the force F on a charge 'q' due to a uniformly charged spherical shell of radius R carrying charge Q distributed uniformly over it. Which one of the following statements is true for F, if 'q' is placed at distance r from the centre of the shell?

$${1 \over {4\pi {\varepsilon _0}}}{{qQ} \over {{R^2}}} > F > 0$$ for r < R

$$F = {1 \over {4\pi {\varepsilon _0}}}{{qQ} \over {{r^2}}}$$ for r > R

$$F = {1 \over {4\pi {\varepsilon _0}}}{{qQ} \over {{r^2}}}$$ for all r

$$F = {1 \over {4\pi {\varepsilon _0}}}{{qQ} \over {{R^2}}}$$ for r < R

JEE Main 2020 (Online) 6th September Evening Slot

MCQ (Single Correct Answer)

-1

Two identical electric point dipoles have dipole moments $${\overrightarrow p _1} = p\widehat i$$ and $${\overrightarrow p _2} = - p\widehat i$$ and are held on the x axis at distance '$$a$$' from each other. When released, they move along the x-axis with the direction of their dipole moments remaining unchanged. If the mass of each dipole is 'm', their speed when they are infinitely far apart is :

$${p \over a}\sqrt {{3 \over {2\pi { \in _0}ma}}} $$

$${p \over a}\sqrt {{1 \over {\pi { \in _0}ma}}} $$

$${p \over a}\sqrt {{1 \over {2\pi { \in _0}ma}}} $$

$${p \over a}\sqrt {{2 \over {\pi { \in _0}ma}}} $$

JEE Main 2020 (Online) 6th September Morning Slot

MCQ (Single Correct Answer)

-1

Charges Q₁ and Q₂ are at points A and B of a right angle triangle OAB (see figure). The resultant electric field at point O is perpendicular to the hypotenuse, then
$${{{Q_1}} \over {{Q_2}}}$$ is proportional to : JEE Main 2020 (Online) 6th September Morning Slot Physics - Electrostatics Question 191 English

JEE Main 2020 (Online) 6th September Morning Slot Physics - Electrostatics Question 191 English

$${{x_1^3} \over {x_2^3}}$$

$${{x_2^2} \over {x_1^2}}$$

$${{{x_1}} \over {{x_2}}}$$

$${{{x_2}} \over {{x_1}}}$$

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