PName:__________________________Q1. An important principle that you learnt about in lecture is “superposition.” The use of superposition depends on a clear understanding of vector sums. What is the vector sum of the three vectors shown below? They all have the same magnitude.Physics Pre-lab 212P-2Electric Fields and SuperpositionName:__________________________Section:_____ Date:__________(Read this & answer the questions before coming to lab)Summary of relevant concepts: (a) The electric field at any point in space is defined as the force experienced by a test charge of+1 C. Hence, the magnitude of the electric field at a distance r from a SINGLE point chargeQ is given by Coulomb's Law:2rQkE  where k = 8.99 x 109 N-m2/C2.(b) The electric field from a COLLECTION of POINT charges is given by the vector sum ofthe electric fields from all the individual point charges (“superposition”). (c) Electric field lines provide a convenient way of visualizing the electric field in any region ofspace:- Electric field lines originate at positive charges and terminate at negative charges;- The electric field at any given position is tangential to the electric field line;- The spacing between electric field lines is inversely proportional to the strength of theelectric field: i.e. they are closer together where the field is stronger, and further apartwhere the field is weaker.(d) A common arrangement of charges in Nature is the electric dipole. This consists of twocharges equal in magnitude Q but of opposite sign, separated by a distance a. An electricdipole is characterized by the dipole moment p= Qa. This is a vector that points from thenegative charge towards the positive charge.Pre-lab Questions:Q1. An important principle that you learnt about in lecture is “superposition.” The use ofsuperposition depends on a clear understanding of vector sums. What is the vector sum of thethree vectors shown below? They all have the same magnitude.Magnitude of resultant vector = _________________________Direction of resultant vector = ___________________________Q2. The figure below shows 4 positive charges of equal magnitude arranged on a semicirclecentered about the origin. What is the direction of the net electric field produced at the origin?Direction of electric field = _______________________________________120012001200xy450450Now, use superposition to calculate the direction and magnitude of the electric field at a point Pthat lies on the perpendicular bisector of an electric dipole. (See figure below.) Your goal is tofirst determine the electric field at any general value of r, and then in the limit r >> a. Q3. In the diagram above, draw vectors that represent the electric field produced at P by eachcharge. Also, draw a vector that represents the net electric field produced by the sum of these twovectors.Q4. From the vector diagram that you used above, derive an exact expression for the magnitudeof the electric field at P. The only parameters in your final expression should be the dipolemoment p = Qa, the distance r, the distance a and the constant k from Coulomb's Law. Call thisexpression "Equation 1." (You will need it in the lab activity.)P+Q-QraQ5. Simplify your analytical expression for E(r) for large distances i.e. r >> a. You shouldobtain a particularly simple expression. Call this expression "Equation 2." (Needed later in labactivity.)Q6. A rule of thumb calculation (no calculators!). Suppose you are at some distance r from anelectric dipole, such that r is much larger than the dipole separation a. You measure themagnitude of the electric field from the dipole to be 0.001 N/C. If you double your distance fromthe dipole, approximately what is the magnitude of the electric