Two thin metal plates are placed close to each other. On the inner side, both plates have a surface charge density of 2.9 × 10−11 C m−2, but of opposite nature. Between the plates, what is the electric force exerted in per unit area ?
5.5 × 10 -11 N/m2
9.5 × 10 -11 N/m2
5.5 × 10 -12 N/m2
9.5 × 10 -12 N/m2
Two point charges +1.5 µC and −0.5 µC are located 1 m apart. There is a point P on the line joining the charges where the net potential is zero. What is the distance of point P from charge +1.5 µC ?
0.50 m
0.75 m
0.35 m
0.25 m
Two charges, +2 µC and +8 µC, are placed 0.1 m apart. Another charge is placed between the two, which brings the system in equilibrium.What is the magnitude of the third charge?
0.75 µC
0.87 µC
2.50 µC
1.25 µC
An electron accelerated through 30-kV, in a cathode ray oscilloscope, enters a system of deflecting plates. The deflecting field between the plates is 24 kV m−1. The length of the deflecting plates is 0.06 m and the total deflection produced in the path of the electron on a screen is 9 mm.What is the distance of the screen from the near end of the plates?
0.38 m
0.40 m
0.45 m
Two positively charged particles, each carrying a charge of 3.6 × 10−8 C and having the same mass, are located at a distance of 0.1 m away from each other. If the electrostatic force on one of the charges is equal to its weight, then the mass of the system is :
1.019 g
1.182 g
0.854 g
0.238 g
Four charges q, 2q, 3q and 4q are located at the vertices of a square of side a (as shown in the given figure). k is the electrostatic constant. What is the sum of the magnitude of forces exerted on each charge?
The bob of a pendulum of mass 100 g is at equilibrium in a horizontal uniform electric field of 2.5 × 105 V m−1. In this equilibrium position, the pendulum makes an angle with the vertical. The amount of charge on the bob is 3 µC. Assume that the bob is suspended by means of a thin mass-less string. What will be the tension in the string when the bob is at equilibrium?
0.75 N
1.23 N
0.75 × 102 N
1.23 × 102 N
A charge experiences a force of 32 N as it is placed at a certain distance on the axial line of an electric dipole.What will be the force on the charge if its distance from the dipole is halved?
64 N
128 N
256 N
512 N
The electric field intensity of a point P at a distance of 0.30 m from the centre of a Gaussian charged sphere of radius 0.20 m is 2.5 × 103 N C-1, directed radically outwards. What is the electric flux emanating through the given Gaussian surface?
2.82 × 103 N m2C-1
1.25 × 103 N m2C-1
0.63 × 103 N m2 C-1
0.31 × 103 N m2C-1
Two charged particles are located at a distance of 1.5 m. The force of attraction between the charges is 2.1 × 10−7 N. One particle has a charge equal to two thirds the charge of another particle. What is the value of charges on the two particles?
