# BASIC ELECTRONICS Test 18

Student’s Name:____________Admission No.______Roll No._____Section:______
Paper: Physics      Class: 10                    Time Allowed:    One Hour                           Marks: 25

Q1. Circle the correct answer.  (10)

1.Transfer is used to change the value of:
a) Voltage                 b) power                  c) Energy                d) Potential
2.In a practical electric motor, the coil is called:
a) armature               b) coil                c) electromagnet                d) all of these
3.The lines of force of a coil are directed……………to its plane.
a) parallel               b) anti parallel                      c) perpendicular                d) inclinde
4.Which statement is true about the magnetic poles?
a) unlike pole repel                                 b) like pole attract                                                                                c) magnetic poles do noteffect each other                 d) a single magnetic pole does not exist
5.If we increase the number of loops,the turning effect:
a) increase slightly                 b) increase greatly                c) decrease suddenly              d) remains same
6.Which rule is used to find direction of the force on a current carrying wire in a magnetic field?
a) right hand rule               b) Fleming’s left hand rule          c) head to tail rule           d) Hero’s formula
7.Which of the following have two coils, primary and secondary?
a) transformer           b) ac generator                 c) dc motor                d) none of these
8.The phenomenon of production of induced current in one coil due to change of current in a neighbouring coil is called:
a) electromagnetic induction                            b) electrostatic induction                                                      c) mutual induction                                            d) self induction
9.Who found the direction of induced e.m.f. first time?
a) lenz                b) henry                c) newton                d) bohar
10.The direction of magnetic lines of force can be determined by:
a) left hand rule              b) right hand rule            c) head to tail rule                d) None of these

Q2. Write short answers to these questions: (15)
1.What is a electromagnet?
2.State Fleming’s left hand rule.
3.What is transformer?
4.What is relay? How it works?
5.What is the function of split Rings in the D.c motor.