I need some help in Electric force and electric field.there are some MCQ.PLz i don't know the answers?

Question

13) An object becomes temporarily electrified if a charged object is placed near it. This
method of electrification is called
a) charging by friction b) charging by contact
c) charging by conduction d) charging by induction
e) charging by insulation

17) A point charge is placed in an electric field that varies with position. No force is
exerted on the charge
a) at positions where the potential is zero
b) at positions where the electric field is zero
c) when it is perpendicular to the electric field
d) when it is moving parallel to the electric field
e) if it is completely surrounded by other charges

18) The work per unit charge needed to move an electrical charge between two points is
measured in
a) joules b) volts
c) coulombs d) Newton/meter
e) Newton/coulomb

Answer 1

Here are some basic definitions which should help you. Electric field is electric force/ unit charge and electric potential is electric potential energy/ unit charge.

13. A, B, and C are all the same thing, charging an object through physical contact so none of these are correct. E does not make sense, so D must be the correct answer.

17 a. Potential equal to zero only means that potential energy per unit charge at that location is equal to zero. It says nothing about the force on the charge.

b. Is the correct answer, Electric field is the force exerted on the particle per unit charge.

c and d. do not make sense.

e. Possible, but you can still have a net force depending on the distance and magnitude of the other charges.

18. Work/charge = energy/charge = potential, so volts or joule/coulomb is the correct answer.

Answer 2

comprehensive electric powered field power = E1 + E2 E1 = kQ1/r1² E2 = kQ2/r² the place Q is the cost of fee r is the gap E1 = (8.99x10^9)(55x10^-9)/((0.02)+(0.0305))² E2 = (8.99x10^9)(55x10^-9)/((0.02)+(0.0305))² electric powered field power = 387765.9 N/C