CH1 CQ

• Consider two metallic rods mounted on insulated supports.  One is neutral, another positively charged.  The charged rod is brought close to the neutral one (no touching!) and at this time the neutral rod was briefly grounded. (for instance, touched by hand).  What would be resulting charge (if any) on initially neutral rod?

  It will be negatively charged
• We have three identical metallic spheres A, B, C. Initially sphere A is charged with charge Q, meanwhile B and C are neutral. Sphere A is brought into contact with sphere B, then disconnected. After this sphere A is brought into contact with sphere C and disconnected again. Finally sphere A is brought into contact with sphere B again and disconnected. What is final charge of sphere A?

  3Q/8
• Two point charges, Q1 and Q2, are separated by a distance R. If the magnitudes of both charges are tripled and their separation is also tripled, what happens to the electrical force that each charge exerts on the other one?

  It stays the same
• Two tiny spheres of identical masses carry charges 1 and 5 mCrespectively. They are brought close to each other and then released.  Which of the following statements is true about  their motion?

  Their accelerations are equal in magnitude.
• Two equal in magnitude, positive charges  +Q are fixed at distance 2d from each other.  The third charge, of magnitude +q is positioned very carefully into the midpoint on the line connecting the first two charges.  Pick the statement which is correct:

  The third charge will be in equilibrium and this equilibrium is stable.
• Charge +Q is positioned at the origin. Charge +2Q is positioned at x=+d. In what part of x you can find a point, where net electric field is 0?

  In part 0<x<d
• Charge +Q is positioned at the origin. Charge -2Q is positioned at x=+d. In what part of x you can find a point, where net electric field is 0?

  In part x<0
• Two very small charged balls of mass m are dropped into frictionless tube as shown in the picture.  Each of balls carries charge Q and as result system comes into equilibrium: these balls are at distance d from each other.  If a charge on the lower ball is halved, the new equilibrium distance will be:

  d/sqrt(2)

  
• Four charges are arranged into a square as it is shown. Direction of electric field in the center of a square is:

  S

  
• Two particles, A and B have the same charge +q, but mass of particle A is twice the mass of particle B. They both start from rest in electric field E. We can conclude that after time t particle A will cover:

  1/2 distance of B
• Two particles, A and B have the same charge +q, and the same mass m. They both enter area with uniform electric field anti-parallel to their velocities. But particle A enters this area with speed twice as big than speed of particle B.  We can conclude that particle A before coming to momentarily stop will cover distance

  4 times larger than covered my particle B