An electric dipole is held in a uniform electric field. (i) Show that the net force acting on it is zero. (ii) The dipole is aligned parallel to the field. Find the work done by rotating it through the angle of 180°. [CBSE (AI) 2012] Open Answer »
Answer the following questions. (i) An electrostatic field line is a continuous curve. That is, a field line cannot have sudden breaks. Why is it so? (ii) Explain why two field lines never cross each other at any point. Open Answer »
Given a uniform electric field E = 5 × 10^3 i N/C, find the flux of this field through a square of 10 cm on a side whose plane is parallel to the Y-Z plane. What would be the flux through the same square if the plane makes a 30° angle with the X-axis? [CBSE Delhi 2014] Open Answer »
Calculate the amount of work done in rotating a dipole, of dipole moment 3 × 10^-8 Cm, from its position of stable equilibrium to the position of unstable equilibrium, in a uniform electric field of intensity 10^4 N/C. [CBSE (F) 2011] Open Answer »
Figure shows two large metal plates P1 and P2, tightly held against each other and placed between two equal and unlike point charges perpendicular to the line joining them. (i) What will happen to the plates when they are released? (ii) Draw the pattern of the electric field lines for the system. [CBSE (F) 2009] Open Answer »
The sum of two point charges is 7µ C. They repel each other with a force of 1 N when kept 30cm apart in free space. Calculate the value of each charge. [CBSE (F) 2009] Open Answer »
Two concentric metallic spherical shells of radii R and 2R are given charges Q1 and Q2 respectively. The surface charge densities on the outer surfaces of the shells are equal. Determine the ratio Q1 : Q2. [CBSE (F) 2013] Open Answer »
Answer the following questions: (a) Define electric flux. Write its SI unit. (b) “Gauss’s law in electrostatics is true for any closed surface, no matter what its shape or size is.” Justify this statement with the help of a suitable example. [CBSE Allahabad 2015] Open Answer »
Plot a graph showing the variation of coulomb force (F) versus 1/r², where r is the distance between the two charges of each pair of charges: (1 µC, 2 µC) and (2 µC, – 3 µC). Interpret the graphs obtained. [CBSE (AI) 2011] Open Answer »
Two equal balls having equal positive charge ‘q’ coulombs are suspended by two insulating strings of equal length. What would be the effect on the force when a plastic sheet is inserted between the two? [CBSE AI 2014] Open Answer »