# Problem in electrostatics: E-field near 2 point charges

• ubergewehr273
In summary, the conversation discusses a homework problem involving charges and potential energy. The participants conclude that option a is incorrect due to unequal magnitudes of the charges, and options c and d are correct. They also mention difficulty in calculating the angle beta, but agree that it is not necessary to do so to disqualify option b. The problem is from an exam paper called NEST, conducted in India in 2016.
ubergewehr273

Refer the image.

## Homework Equations

kq1q2/r^2 = F
Potential energy = kq1q1/r

## The Attempt at a Solution

Obviously since both charges are unequal in magnitude option a is incorrect.
Calculating field at large distance r,
E = kq1/r^2 - kq2/r^2
= kq2/r^2
Also potential energy at q1 is lesser than near q2 for negative charge.
So options c,d are correct. However I don't understand how the angle beta can be calculated from the given information.

#### Attachments

• Screenshot-2018-5-26 master_A dvi - NEST2016_A pdf.png
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ubergewehr273 said:
However I don't understand how the angle beta can be calculated from the given information.
No need to calculate the angle to disqualify answer b.

Doc Al said:
No need to calculate the angle to disqualify answer b.
I'm sorry but I don't quite understand. The answers given are b,c,d.

Hmm. What book is this from?

Doc Al said:
Hmm. What book is this from?
It's from an exam paper called NEST (National Entrance Screening Test) conducted in India. Its for the year 2016.

## What is electrostatics?

Electrostatics is the study of electric charges at rest. It involves studying the behavior of electric charges and the electric fields they create.

## What is an E-field?

An E-field, or electric field, is a region in which an electric charge experiences a force. It is a vector field that can be represented by electric field lines.

## How is the E-field near 2 point charges calculated?

The E-field near 2 point charges can be calculated using Coulomb's Law, which states that the force between two point charges is directly proportional to the product of their charges and inversely proportional to the square of the distance between them.

## How does the E-field change as the distance between the 2 point charges changes?

The E-field between 2 point charges decreases as the distance between them increases. This is because the force between the charges decreases as the distance increases.

## What are some real-life applications of studying the E-field near 2 point charges?

Studying the E-field near 2 point charges is important in understanding the behavior of electric charges and how they interact with each other. This knowledge is crucial in many applications such as designing electronic devices, understanding lightning strikes, and creating new technologies such as capacitors and batteries.

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