Equipotentials at a great distance from a collection of charges whose total sum is not zero are approximately [NCERT Exemplar]
Two small spheres each carrying a charge q are placed r metre apart. If one of the spheres is taken around the other one in a circular path of radius r, the work done will be equal to
The electric potential V at any point O (x, y, z all in metres) in space is given by V = 4x² volt. The electric field at the point (1 m, 0, 2 m) in volt/metre is
Answer: 8 along negative x-axis
If a unit positive charge is taken from one point to another over an equipotential surface, then
A hollow metal sphere of radius 5 cm is charged so that the potential on its surface is 10 V. The potential at the centre of the sphere is
The electrostatic force between the metal plates of an isolated parallel plate capacitor C having a charge Q and area A, is
Answer: independent of the distance between the plates.
A capacitor is charged by a battery. The battery is removed and another identical uncharged capacitor is connected in parallel. The total electrostatic energy of resulting system
Answer: decreases by a factor of 2.
A conductor with a positive charge
Answer: may be at +ve, zero or -ve potential.
Which of the following options are correct? If a conductor has a potential V 4- 0 and there are no charges anywhere else outside, then [NCERT Exemplar]
Answer: there cannot be any charge in the body of the conductor.
Which of the following options is correct? In a region of constant potential [NCERT Exemplar]
Answer: the electric field is zero.
64 drops each having the capacity C and potential V are combined to form a big drop. If the charge on the small drop is q, then the charge on the big drop will be
The radii of two metallic spheres A and B are r1 and r2 respectively (r1 > r2). They are connected by a thin wire and the system is given a certain charge. The charge will be greater
Answer: on the surface of the sphere A.
In parallel combination of n cells, we obtain
Combine three resistors 5 Q, 4.5 Q and 3 Q in such a way that the total resistance of this combination is maximum
In the series combination of two or more than two resistances
Answer: the current through each resistance is same.
An electric heater is connected to the voltage supply. After few seconds, current gets its steady value then its initial current will be
Answer: slightly higher than its steady current
The resistivity of alloy manganin is
Answer: Nearly independent of temperature
A charge is moving across a junction, then
When there is an electric current through a conducting wire along its length, then an electric field must exist
Answer: inside the wire but parallel to it.
A Daniel cell is balanced on 125 cm length of a potentiometer wire. Now the cell is short-circuited by a resistance 2 ohm and the balance is obtained at 100 cm. The internal resistance of the Daniel cell is