Name:__________________________TemplateMoving Charges & Magnetic FieldsLab Activity 1: A Magnetic Field Exerts A Force On Moving Charges(Measuring the Charge-to-Mass Ratio for Electrons)Name:__________________________Physics Pre-lab 212P-8TemplateMagnetic Fields and Electric CurrentName:__________________________Section:_____ Date:__________(Read this & answer the questions before coming to lab)Pre-lab Questions:A. Force exerted by a magnetic field on a moving charge:Suppose an electron (charge e, mass m) is accelerated from rest through a potential difference V.It then enters a region of uniform magnetic field B, as shown in the figure below. The electron ismoving in the plane of this page and the magnetic field is perpendicular out of the page. Answerthe following questions based on this information. You will need these answers in the labactivity.Q1. Determine an expression for the speed v of the electron just before it enters the magneticfield. (Hint: use energy conservation.) Penn State University Physics 212P-8 Written by Redwing and Samarth 1Potentialdifference = VB Penn State University Physics 212P-8 Written by Redwing and Samarth 2Q2. Describe qualitatively why the electron moves in a circle once it enters the region ofuniform magnetic field. Does the speed remain constant? ____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________Q3. Derive an equation for the charge-to-mass ratio e/m. The equation should contain theaccelerating voltage V, the radius r of the electron's trajectory and the magnetic field B.  Penn State University Physics 212P-8 Written by Redwing and Samarth 3Q4. Using your result for Q3, what is the slope of the plot 1/r versus B equal to?Q5. What approximately is the magnitude of the earth's magnetic field?B. Magnetic Force on a CurrentQ6. Use your compass to determine which end of your magnet is "North." Position your magnetwith the N pole immediately below a roughly horizontal straight portion of your wire. Note downthe direction in which current will flow when the circuit is completed. Watch the reaction of thereaction of the wire when you connect the battery for a few seconds. Repeat the experiment with(a) the current direction reversed and (b) with the S pole of the magnet pointing upwards.Describe and explain the reaction of the wire using F = iL x B.______________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ Penn State University Physics 212P-8 Written by Redwing and Samarth 4Physics Lab 212P-8TemplateMoving Charges & Magnetic Fields NAME: ____________________________________LAB PARTNERS: ________________________________________________________________________LAB SECTION: __________________________LAB INSTRUCTOR: __________________________DATE: __________________________EMAIL ADDRESS: __________________________ Penn State University Physics 212P-8 Written by Redwing and Samarth 5Lab Activity 1: A Magnetic Field Exerts A Force On Moving Charges(Measuring the Charge-to-Mass Ratio for Electrons)Q1. Record (in the table below) the current I through the Helmholtz coils and the diameter d ofthe circular electron path. Make sure that you convert the diameter into meters. Repeat thisprocedure for 10 different values of the current I.I (A) Diameter of Circle d (m)Q2. Plot (1/r) vs. B. Deduce an average value for the ratio e/m, including standard error, byfitting the data to a straight line. (Use your result from Q4 of the pre-lab. The standard error isgiven by )(4)(11aSEVameSE ∗=, where a1 is the slope of 1/r versus B, V is the powersupply voltage and SE(a1) is the standard error of the slope obtained from your Excel graph.)Compare your measured value with the established one: 1.756 x 1011 C/kg. Include your Excelspreadsheet, graph and any relevant analysis with your report.________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ Penn State University Physics 212P-8 Written by Redwing and Samarth 6Lab Activity 2: Moving Charges Create A Magnetic Field(Magnetic Field Of A Current-carrying Wire)Q3. For the polarity of the batteries shown above, the conventional current in the wire travelsvertically upwards. Use the Biot-Savart Law and/or a "right hand rule" to qualitatively sketch themagnetic field lines produced by this current. Q4. While viewing your experimental set up from above, complete the following diagram toshow the compass needle direction without and with current in the wire. One of the compasslocations has been filled in for you. Penn State University Physics 212P-8 Written by Redwing and Samarth 7N Without Current With Current Penn State University Physics 212P-8 Written by Redwing and Samarth 8Q5. By your observations in Q4, did the field produced by the current in the wire have a largermagnitude than the Earth's magnetic field? Do your results of Q4 confirm your expectations forthe magnetic field produced by the current in the wire? Explain clearly why or why not?______________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________Q6. What do you expect will happen to the magnetic field lines if