Q 1.6: Four point charges q_{A}= 2 \mu C, q_{B}= -5 \mu C, q_{C}= 2 \mu C, and q_{D}= -5 \mu C are located at the corners of a square ABCD of side 10 cm. What is the force on a charge of 1 μC placed at the centre of the square?

Answers (1)

Charges at (A, C) and (B, D) are pairwise diametrically opposite and also equal.

Therefore, their force on a point charge at the centre of the square will be equal but opposite in directions.

Now, AC = BD = \sqrt{2}\times(10\times10^{-2} m) = \sqrt{2}\times0.1 m

\therefore AO = BO = CO = DO = r = Half of diagonal = \sqrt{2}\times0.05 m

Force on point charge at centre due to charges at A and C = F_{A} = -F_{C} = \frac{k(2\mu C)(1\mu C)}{(r)^2}

Similarly, Force on point charge at centre due to charges at B and D = F_{B} = -F_{D} = \frac{k(-5\mu C)(1\mu C)}{(r)^2} 

\therefore Net force on point charge =  \\F_{A} + F_{B} + F_{C} + F_{D} \\

                                               = -F_{B} +F_{B} - F_{D} + F_{D} = 0.

Hence, the charge at the centre experiences no force.

Preparation Products

JEE Main Rank Booster 2021

This course will help student to be better prepared and study in the right direction for JEE Main..

₹ 13999/- ₹ 9999/-
Buy Now
Rank Booster NEET 2021

This course will help student to be better prepared and study in the right direction for NEET..

₹ 13999/- ₹ 9999/-
Buy Now
Knockout JEE Main April 2021 (Subscription)

An exhaustive E-learning program for the complete preparation of JEE Main..

₹ 6999/- ₹ 4999/-
Buy Now
Knockout JEE Main April 2022 (Subscription)

Knockout JEE Main April 2022 Subscription.

₹ 8999/- ₹ 5999/-
Buy Now
Knockout NEET May 2021 (Subscription)

An exhaustive E-learning program for the complete preparation of NEET..

₹ 4999/-
Buy Now
Exams
Articles
Questions