Two small sphere balls each carrying charge q = 10µC are suspended by two insulated threads of equal length 1m each, from a point fixed in the ceiling. It is found that in equilibrium, threads are separated by an angle 600 between them as shown in figure, the tension in the thread is
Let tension in the thread is T, then force of repulsion between the charges.
F = T cos 60°
The charge on two identical metalic balls are +40µC and -10µC respectively and they are separated at 2.0m.How much and nature of force will act between them?
If a body is charged by rubbing it, its weight
The body may slightly get charged either negatively or positively.
In S.I system, the value of is
Dimensions of are
The dielectric constant K of an insulator can be :
Dielectric constant of a material is K > 1.
Choose the correct statement :
Net charge of universe is constant. Positive and nagative charges may separately be created or destroyed. But net sum of charge remains constant.
Two neutrons are placed at some distance apart from each other. They will
There will be gravitational attraction between the neutrons.
There are two charges +1 µC and +5 µC. The ratio of the forces (force on one due to other) acting on them will be
Newton's third law.
Five balls numbered 1, 2, 3, 4, 5 are suspended using separate threads. The balls (1, 2), (2, 4) and (4, 1) show electrostatic attraction, while balls (2,3) and (4, 5) show repulsion, Therefore, ball 1 must be
If 1 is positively charged, then 2 should be negatively charged, then 4 should be positively charged. Now, 1 and 4 cannot attract. It means ball 1 should be neutral (2 and 4 cannot be neutral because they are showing repulsion with 3 and 5, respectively).
Electric charges A and B repel each other, Electric charges B and C also repel other. If A and C are held close together, they will.
A and B have like charges, and B and C have like charges. So, A and C also have like charges. Hence, they also repel each other.
Two point charges repel each other with a force of 100 N One of the charges is increased by 10% and the other is reduced by 10%. The new force of repulsion at the same distance would be
Two positive and equal charges are fixed at a certain distance. A third small charge is placed in between the two charges and it experiences zero net force due to the other two.
The equilibrium can be stable only if on displacing the small charge slightly in any direction, the forces act on it in such a way so as to bring back the charge to its equilibrium position.
An isolated charge q1 of mass m is suspended freely by a thread of length l. Another charge q2 is brought near it (r>> l). W hen q1 is in equilibrium, tension in thread will be
Initial tension : T1 = mg
Final tension : T2 cos θ = mg
Obviously, T2 > mg.
Here we have assumed θ to be small so that F is almost horizontal.
A point charge q1, is moved along a circular path of radius r in the electric field of another point charge q2 at the centre of the parh. The work done by the electric field on the charge q1 in half revolution is
As the force's always perpendicular, therefore work done is always zero.
A spherical conducting ball is suspended by a grounded conducting thread. A positive point charge is moved near the ball. The ball will
It will get attracted due to induction.
Five point charges, each of value +q, are placed on five vertices of a regular hexagon of side L. The magnitude of the force on a point charge of value -q coulomb placed the centre of the hexagon is
If all charges were present force on central charge will be zero.
The sure test of electrification is :
Attraction m ay take place between charged and uncharged body too. So, repulsion is the surest test of charge.
The number of electrons in one coulomb of charge will be :
The minimum value of charge on any charged body may be :
Minimum charge is the electronic charge.
W hen 1014 electrons are removed from a neutral metal sphere, the charge on the sphere becomes
Charge on the body will be
One metallic sphere A is given a positive charge whereas another metallic sphere B of exactly the same mass is given a negative charge. Then
Positively charged body loses some mass whereas negatively charged body gains some mass.
An electron has charge 1.6 × 10-19 coulomb when at rest. When it moves with speed 0.8c the charge on the electron would be (c being speed of light in vacuum)
Charge is invarient in nature.
A charged rod attracts bits of dry cork dust which after touching the rod
On touching it shares charge and then idential charges repel.
The electrostatic force between two point charges q1 and q2 at separation r is given by
The constant K
So k depends on medium as well as system of units.
A charge q1 exerts some force on a second charge q2.If third charge q3 is brought near, the force of q1 exerted on q2
Due to principle of superposition force will not depend upon presence of another charge.
If Fe and Fg are electric and gravitational force, respectively between two electrons situated at certain distance apart, then the ratio of Fe and Fg is of the order of
A thin stream of water from a tap is attracted by placing a rod near it. The rod is
The charge on rod attracts the stream of water due to induction.
The proton is 1836 times heavier than electron. The Coulomb's force of repulsion between two protons at a certain distance between them is F. Then the Coulomb force between two electrons for same distance would be :
Coulomb's force does not depend upon mass.
The electric field intensity at a point situated 4 meters from a point charge is 200 N/C. If the distance is reduced to 2 meters, the field intensity will be