Two charges of equal amount +Q are placed on a line. Another charge q is placed at the mid-point of the line. The system will be in equilibrium if the value of q is
- $\frac{Q}{4}$
- $-\frac{Q}{2}$
- $+\frac{Q}{2}$
- $+\frac{Q}{4}$
The Correct Option is A
Solution and Explanation
Force on +Q charge,$\frac{KQ^{2}}{\ell^{2}} =\frac{KQq}{\ell^{2}} \times4$
$q=\frac{-Q}{4}$
Top Questions on Electric Charge
- An electric dipole consists of charges \(\pm 4 \mu C\) separated by a distance of \(6\,cm\). Calculate the electric field at a point on the axial line at a distance \(20\,cm\) from its center.
- If the protons and electrons are the only basic charges in the universe, all the observable charges have to be integral multiples of e. Thus, if an object contains x electrons and y protons, the net charge on the object will be
- CUET (UG) - 2025
- Physics
- Electric Charge
- The force between two point charges separated by a distance \(d\) is \(F\). If one charge is moved away by a distance \(d\), then the new force is:
- KEAM - 2025
- Physics
- Electric Charge
- Force between two point charges \( q_1 \) and \( q_2 \) placed in vacuum at a distance \( r \, \text{cm} \) apart is \( F \). Force between them when placed in a medium having dielectric \( K = 5 \) at \( r/5 \, \text{cm} \) apart will be:
- MHT CET - 2024
- VITEEE - 2024
- Physics
- Electric Charge
Two point charges M and N having charges +q and -q respectively are placed at a distance apart. Force acting between them is F. If 30% of charge of N is transferred to M, then the force between the charges becomes:
- COMEDK UGET - 2024
- Physics
- Electric Charge
Questions Asked in WBJEE exam
- The variation of displacement with time of a simple harmonic motion (SHM) for a particle of mass \( m \) is represented by: \[ y = 2 \sin \left( \frac{\pi}{2} + \phi \right) \, \text{cm} \] The maximum acceleration of the particle is:
- WBJEE - 2025
- simple harmonic motion
- Ruma reached the metro station and found that the escalator was not working. She walked up the stationary escalator with velocity \( v_1 \) in time \( t_1 \). On another day, if she remains stationary on the escalator moving with velocity \( v_2 \), the escalator takes her up in time \( t_2 \). The time taken by her to walk up with velocity \( v_1 \) on the moving escalator will be:
- WBJEE - 2025
- Relative Motion
- A force \( \mathbf{F} = ai + bj + ck \) is acting on a body of mass \( m \). The body was initially at rest at the origin. The co-ordinates of the body after time \( t \) will be:
- WBJEE - 2025
- Newtons Laws of Motion
A quantity \( X \) is given by: \[ X = \frac{\epsilon_0 L \Delta V}{\Delta t} \] where:
- \( \epsilon_0 \) is the permittivity of free space,
- \( L \) is the length,
- \( \Delta V \) is the potential difference,
- \( \Delta t \) is the time interval.
The dimension of \( X \) is the same as that of:- WBJEE - 2025
- Dimensional Analysis
- Which logic gate is represented by the following combination of logic gates?
- WBJEE - 2025
- Logic gates
Concepts Used:
Electric Charge
What is Electric Charge
It is the property of subatomic particles that experiences a force when put in an electric and magnetic field. It is are of two types: Positive and Negative. It commonly carried by charge carriers protons and electrons.
Properties of Electric Charge
Various properties of charge include the following :-
- Additivity of Electric Charge
- Conservation of Electric Charge
- Quantization of Electric Charge
Types of electric charge
Two kinds of electric charges are there :-
Negative Charge - When an object has a negative charge it means that it has more electrons than protons.
Positive Charge - When an object has a positive charge it means that it has more protons than electrons.
When there is an identical number of positive and negative charges, the negative and positive charges would cancel out each other and the object would become neutral.