# BASIC ELECTRONICS Test 10

Paper: Physics      Class: 10                    Time Allowed:    One Hour                           Marks: 25

Q1. Circle the correct answer.  (10)

1.In a practical electric motor, the coil is called:
a) armature               b) coil               c) electromagnet                        d) all of these
2.If we increase the number of loops,the turning effect:
a) increase slightly                b) increase greatly                   c) decrease suddenly                  d) remains same
3.Which statement is true about the magnetic poles?
a) unlike pole repel                        b) like pole attract                                                                                                                                                               c) magnetic poles do not  effect each other                    d) a single magnetic pole does not exist
4.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
5.Who found the direction of induced e.m.f. first time?
a) lenz                 b) henry              c) newton                d) bohar
6.Transfer is used to change the value of:
a) Voltage               b) power                c) Energy                d) Potential
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.The lines of force of a coil are directed……………to its plane.
a) parallel             b) anti parallel              c) perpendicular              d) inclinde
10.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

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